Flush water tank apparatus and flush toilet apparatus provided with the same

ABSTRACT

Provided are a flush water tank apparatus capable of restraining instability of an operation of a piston and restraining fluctuations in a water pressure of flush water discharged from a first discharge part provided separately from an inlet, and a flush toilet apparatus including the flush water tank apparatus. A discharge valve hydraulic drive portion of a flush water tank apparatus of the present invention includes a cylinder, a piston, and a rod extending from the piston through a through-hole portion formed in the cylinder, the cylinder including an inlet into which flush water flows, a first discharge part that is provided separately from the inlet to drain the flush water, and a second discharge part that is provided separately from the first discharge part and is formed between the rod and the through-hole portion and between the piston and the through-hole portion.

TECHNICAL FIELD

The present invention relates to a flush water tank apparatus, and moreparticularly to a flush water tank apparatus configured to supply flushwater to a flush toilet, and a flush toilet apparatus provided with thesame.

BACKGROUND ART

An automatic washing apparatus for a toilet is disclosed in JapaneseUtility Model Laid-Open No. 63-86180. The automatic washing apparatusincludes a hydraulic cylinder that is operated by a pressure of waterbeing supplied, an electromagnetic valve that communicates and shuts offthe supply of tap water to the hydraulic cylinder, and a float valveconfigured to open and close a valve seat. Based on the operation of theelectromagnetic valve, a pressure fluid flows into the hydrauliccylinder, a piston in the hydraulic cylinder ascends, a coupling rod anda coupling chain coupled to the piston ascend, and thus the float valveis pulled up and the float valve is opened. The piston in the hydrauliccylinder is provided with a sealing member that seals a space betweenthe piston and an inner wall of the hydraulic cylinder. A small hole 23a for relief is bored on a lower side of the hydraulic cylinder.

SUMMARY OF THE INVENTION Technical Problem

However, in a flush water tank apparatus disclosed in Japanese UtilityModel Laid-Open No. 63-86180, when a water supply pressure suddenlyfluctuates, for example, suddenly rises during the supply of tap waterto the hydraulic cylinder, since only the small hole 23 a for relief isprovided in the hydraulic cylinder, the operation of the piston maybecome unstable due to an impact of sudden fluctuations in the pressureof the flush water. Therefore, malfunction of the piston may occur orthe toilet may be poorly washed.

Accordingly, an object of the present invention is to provide a flushwater tank apparatus capable of restraining an unstable operation of thepiston and restraining the fluctuations in the pressure of the flushwater drained from a first discharge part provided separately from aninlet, and a flush toilet apparatus including the flush water tankapparatus.

Solution to Problem

In order to solve the above problems, an embodiment of the presentinvention is a flush water tank apparatus configured to supply flushwater to a flush toilet, the flush water tank apparatus including: areservoir tank configured to store flush water to be supplied to theflush toilet and includes a water discharge opening formed thereon, thewater discharge opening being for draining the stored flush water to theflush toilet; a discharge valve configured to open and close the waterdischarge opening to supply the flush water to the flush toilet and tostop the supply of the flush water; and a discharge valve hydraulicdrive portion configured to drive the discharge valve using a watersupply pressure of tap water being supplied, the discharge valvehydraulic drive portion including: a cylinder to which the tap water issupplied as flush water; a piston that is slidably disposed in thecylinder and moves from a first position to a second position by theflush water flowing into the cylinder; a rod that extends from thepiston through a through-hole portion formed in the cylinder to connectthe piston and the discharge valve; an elastic member that is providedon the piston and has a sealing function between the piston and an innerwall of the cylinder; an inlet that is formed in the cylinder and intowhich the flush water flows; a first discharge part that is providedseparately from the inlet to drain the flush water from an inside of thecylinder; and a second discharge part that is provided separately fromthe first discharge part and is formed between the rod and thethrough-hole portion and between the piston and the through-holeportion.

According to the embodiment of the present invention configured in thisway, the cylinder includes the inlet into which the flush water flows,the first discharge part provided separately from the inlet to cause theflush water to drain, and the second discharge part provided separatelyfrom the first discharge part and formed between the rod and thethrough-hole portion. Thereby, when the water supply pressure of theflush water to the cylinder suddenly fluctuates, for example, suddenlyrises in the state where the flow channel is not communicated or iscommunicated from the inlet to the first discharge part in the cylinder,the second discharge part can soften the impact of the suddenfluctuation in the pressure of the flush water, the piston can bufferthe impact applied from the flush water, and the unstable operation ofthe piston can be restrained.

Advantageous Effect of the Invention

According to the present invention, it is possible to provide a flushwater tank apparatus capable of reducing the possibility of theoperation malfunction of the discharge valve hydraulic drive portion,and a flush toilet apparatus including the flush water tank apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing an entire flush toilet apparatusincluding a flush water tank apparatus according to a first embodimentof the present invention;

FIG. 2 is a cross-sectional view showing a schematic configuration ofthe flush water tank apparatus according to the first embodiment of thepresent invention;

FIG. 3 is a side view showing a state where a discharge valve hydraulicdrive portion, a clutch mechanism, and a discharge valve of the flushwater tank apparatus according to the first embodiment of the presentinvention are disposed in a reservoir tank in a standby state;

FIG. 4 is a front cross-sectional view taken along a line IV-IV in FIG.3;

FIG. 5 is a cross-sectional view taken in a front-rear direction along aline V-V in FIG. 4;

FIG. 6 is a partially enlarged view of a vicinity of the discharge valvehydraulic drive portion of the flush water tank apparatus in FIG. 5;

FIG. 7 is a cross-sectional view taken along a line VII-VII in FIG. 6;

FIG. 8 is an exploded perspective view of the clutch mechanism of theflush water tank apparatus according to the first embodiment of thepresent invention;

FIG. 9 is a view showing a state where a piston of the discharge valvehydraulic drive portion is ascending in a cross section of the dischargevalve hydraulic drive portion of the flush water tank apparatus shown inFIG. 5;

FIG. 10 is a view showing s state when the clutch mechanism isdisengaged in the cross section of the discharge valve hydraulic driveportion of the flush water tank apparatus shown in FIG. 5;

FIG. 11 is a view showing a state where the piston of the dischargevalve hydraulic drive portion ascends to a second position in the crosssection of the discharge valve hydraulic drive portion of the flushwater tank apparatus shown in FIG. 5;

FIG. 12 is a view showing a state where the discharge valve descends andthe water discharge opening is closed in the cross section of thedischarge valve hydraulic drive portion of the flush water tankapparatus shown in FIG. 5;

FIG. 13 is a view showing a state where the piston descends and a rodand a movable body attached to the discharge valve come into contactwith each other again in the cross section of the discharge valvehydraulic drive portion of the flush water tank apparatus shown in FIG.5;

FIG. 14 is a cross-sectional view showing a schematic configuration of aflush water tank apparatus according to a second embodiment of thepresent invention;

FIG. 15 is a partially enlarged perspective view of a discharge valvehydraulic drive portion of the flush water tank apparatus shown in FIG.14;

FIG. 16 is a cross-sectional view taken along a line XVI-XVI in FIG. 15;

FIG. 17 is a view showing a state where a piston of the discharge valvehydraulic drive portion in the flush water tank apparatus shown in FIG.14 is moving toward a second position;

FIG. 18 is a view showing a state where a clutch mechanism in the flushwater tank apparatus shown in FIG. 14 is disengaged;

FIG. 19 is a view showing a state where the piston of the dischargevalve hydraulic drive portion in the flush water tank apparatus shown inFIG. 14 is moved to the second position;

FIG. 20 is a view showing a state where a discharge valve in the flushwater tank apparatus shown in FIG. 14 descends and a water dischargeopening is closed;

FIG. 21 is a cross-sectional view showing a schematic configuration of aflush water tank apparatus according to a third embodiment of thepresent invention;

FIG. 22 is a partially enlarged perspective view of a discharge valvehydraulic drive portion of the flush water tank apparatus shown in FIG.21;

FIG. 23 is a front view of the discharge valve hydraulic drive portionshown in FIG. 22 as viewed from a drive part drain passage in an axialdirection of a first rod;

FIG. 24 is a partially enlarged cross-sectional view showing a centralcross section of the discharge valve hydraulic drive portion of theflush water tank apparatus shown in FIG. 21;

FIG. 25 is a view showing a state where a piston of the discharge valvehydraulic drive portion in the flush water tank apparatus shown in FIG.21 is moving toward a second position;

FIG. 26 is a view showing a state where a clutch mechanism in the flushwater tank apparatus shown in FIG. 21 is disengaged;

FIG. 27 is a view showing a state where the piston of the dischargevalve hydraulic drive portion in the flush water tank apparatus shown inFIG. 21 is moved to the second position;

FIG. 28 is a view showing a state where a discharge valve in the flushwater tank apparatus shown in FIG. 21 descends and a water dischargeopening is closed; and

FIG. 29 is a partially enlarged perspective view showing a modificationof the discharge valve hydraulic drive portion of the flush water tankapparatus according to the second embodiment of the present invention.

DETAILED DESCRIPTION OF EMBODIMENTS

A flush toilet apparatus according to a first embodiment of the presentinvention will be described below with reference to the accompanyingdrawings. From the following description, many improvements and otherembodiments will be apparent to those skilled in the art. Accordingly,the following description should be construed as an example only and isprovided for the purpose of teaching those skilled in the art the bestmode of carrying out the present invention. The details of the structureand/or function can be substantially modified and rearranged withoutdeparting from the spirit of the present invention.

FIG. 1 is a perspective view showing an entire flush toilet apparatusincluding a flush water tank apparatus according to the first embodimentof the present invention. FIG. 2 is a cross-sectional view showing aschematic configuration of the flush water tank apparatus according tothe first embodiment of the present invention.

As shown in FIG. 1, a flush toilet apparatus 1 according to the firstembodiment of the present invention includes a flush toilet main body 2which is a flush toilet and a flush water tank apparatus 4 according tothe first embodiment of the present invention which is mounted on a rearportion of the flush toilet main body 2. The flush toilet main body 2 iswashed with flush water supplied from the flush water tank apparatus 4.The flush toilet apparatus 1 according to the present embodiment isconfigured to wash a bowl 2 a of the flush toilet main body 2 by anoperation of a remote controller 6 attached to a wall surface or to washit after a lapse of a predetermined time from a detection of a user'sdeparture by a human sensor 8 provided on a toilet seat, after use. Theflush water tank apparatus 4 according to the present embodiment isconfigured to drain flush water stored therein to the flush toilet mainbody 2 based on an instruction signal from the remote controller 6 orthe human sensor 8 and to wash the bowl 2 a with the flush water.

Further, when a user pushes a button 6 a of the remote controller 6, atoilet washing operation is executed to wash the bowl 2 a. In thepresent embodiment, although the human sensor 8 is provided on thetoilet seat, the present invention is not limited thereto. For example,the human sensor 8 may be provided at a detectable position of user'ssitting, leaving or approaching, withdrawing, and holding out his/herhand, and may be provided on the flush toilet main body 2 or the flushwater tank apparatus 4. In addition, as long as it can detect the user'ssitting, leaving or approaching, withdrawing, and holding his/her hand,an infrared sensor or a microwave sensor can be used as the human sensor8, for example. The remote controller 6 may be replaced with anoperation lever apparatus or an operation button apparatus having astructure capable of mechanically controlling opening and closing of afirst control valve 16 and a second control valve 22 which will bedescribed below.

As shown in FIG. 2, the flush water tank apparatus 4 includes areservoir tank 10 configured to store flush water to be supplied to theflush toilet main body 2, a discharge valve 12 configured to open andclose a water discharge opening 10 a provided in the reservoir tank 10,and a discharge valve hydraulic drive portion (discharge valve hydraulicdrive unit) 14 that is a discharge valve pull-up part configured to pullup the discharge valve 12. Further, the flush water tank apparatus 4includes therein a first control valve 16 that is a water supplycontroller configured to control water supply to the discharge valvehydraulic drive portion 14 from tap water and an electromagnetic valve18 attached to the first control valve 16. Further, the flush water tankapparatus 4 includes therein a second control valve 22 configured tosupply flush water to the reservoir tank 10 and an electromagnetic valve24 attached to the second control valve 22. The flush water tankapparatus 4 includes a float apparatus 26 that is a valve controller anda timing control mechanism configured to hold the pulled-up dischargevalve 12 at a predetermined position.

Further, the flush water tank apparatus 4 includes a clutch mechanism30, and the clutch mechanism 30 connects the discharge valve 12 and arod 32 extending from the discharge valve hydraulic drive portion 14 topull up the discharge valve 12 by an operation of the rod 32 of thedischarge valve hydraulic drive portion 14, and is disengaged at apredetermined timing so that the discharge valve 12 descends. A casing13 is formed above the discharge valve 12, and the casing 13 is formedin a cylindrical shape with an opening on a lower side. The casing 13 isconnected and fixed to the discharge valve hydraulic drive portion 14.

The reservoir tank 10 is a tank configured to store flush water to besupplied to the flush toilet main body 2, and includes a water dischargeopening 10 a formed thereon, which is for draining the stored flushwater to the flush toilet main body 2, at a bottom portion thereof.Further, an overflow pipe 10 b is connected to a downstream side of thewater discharge opening 10 a in the reservoir tank 10. The overflow pipe10 b rises vertically from the vicinity of the water discharge opening10 a, and extends upward from a full water level WL which is stoppedwater level of the flush water stored in the reservoir tank 10. Thestopped water level is a water level of the flush water stored in thereservoir tank 10 in a standby state, and is distinguished from a deadwater level which is a lower limit of the flush water in the reservoirtank 10 at the time of washing the toilet. Therefore, flush waterflowing in from an upper end of the overflow pipe 10 b bypasses thewater discharge opening 10 a and directly flows out to the flush toiletmain body 2.

The discharge valve 12 is a valve main body apparatus disposed to openand close the water discharge opening 10 a, and the discharge valve 12is opened by being pulled up upward, so that the flush water in thereservoir tank 10 is discharged to the flush toilet main body 2 and thebowl 2 a is washed. In addition, the discharge valve 12 closes the waterdischarge opening 10 a to stop the supply of the flush water to theflush toilet main body 2. The discharge valve 12 includes a valve mainbody 12 b having a circular outer shape and configured to open and closethe water discharge opening 10 a, a valve shaft frame body 12 aextending upward from the valve main body 12 b and interlocking with thevalve main body 12 b, and a support portion 12 d (see FIG. 8) formed ina C-shape and receiving the rotary shaft 66. The discharge valve 12 is adirect-acting discharge valve apparatus in which the valve shaft framebody 12 a is moved up and down in a vertical direction to move the valvemain body 12 b up and down in the vertical direction and to open andclose the water discharge opening 10 a. Further, the discharge valve 12is pulled up by a driving force of the discharge valve hydraulic driveportion 14, the clutch mechanism 30 is disengaged at a predeterminedtiming when the discharge valve 12 is pulled up to a predeterminedheight, and the discharge valve 12 descends by its own weight. When thedischarge valve 12 descends, the discharge valve 12 is held by the floatapparatus 26 for a predetermined time, and a time until the dischargevalve 12 is seated on the water discharge opening 10 a is adjusted.

The discharge valve hydraulic drive portion 14 will be described belowwith reference to FIGS. 2 to 7.

As shown in FIGS. 2, 4, and 5, the discharge valve hydraulic driveportion 14 is configured to drive the discharge valve 12 using a watersupply pressure of the flush water supplied from the tap water.Specifically, the discharge valve hydraulic drive portion 14 includes acylinder 14 a to which the tap water supplied from the first controlvalve 16 is supplied as flush water, a piston 28 slidably disposed inthe cylinder 14 a, a rod 32 protruding from a lower end of the cylinder14 a to drive the discharge valve 12, a packing 20 provided on thepiston 28 and being a sealing member having a sealing function betweenthe piston 28 and an inner wall of the cylinder 14 a, and a spring 48provided in the cylinder 14 a and being an urging member that urges thepiston 28 toward the side of a first position H1 (see FIG. 6).

Further, the spring 48 is disposed inside the cylinder 14 a to urge thepiston 28 downward. The clutch mechanism 30 is provided at a lower endof the rod 32, the rod 32 and the valve shaft frame body 12 a of thedischarge valve 12 are coupled and released to and from each other bythe clutch mechanism 30.

The cylinder 14 a has an axis disposed to be directed in the verticaldirection, and the piston 28 is received inside the cylinder 14 a to beslidable in an up-down direction. Further, a drive part water supplypassage 34 a is connected to a lower end of the cylinder 14 a such thatthe flush water flowing out from the first control valve 16 flows intothe cylinder 14 a. The flush water flows into the cylinder 14 a usingthe water supply pressure of the tap water. Therefore, the piston 28 inthe cylinder 14 a is pushed up against an urging force of the spring 48by the flush water flowing into the cylinder 14 a. Only the tap water issupplied to the cylinder 14 a as flush water, and the flush water oncesupplied to the reservoir tank 10 does not flow into the cylinder 14 a.Not only the piston 28 moves up and down in the cylinder 14 a, but alsothe piston 28 may move in another direction (for example, an obliquedirection or a left-right direction) in the cylinder 14 a.

On the other hand, a first discharge part 14 m is provided in an uppercenter of the cylinder 14 a in a height direction to form an outflowhole to the drive part drain passage 34 b, and the drive part drainpassage 34 b communicates with the inside of the cylinder 14 a via thefirst discharge part 14 m. Therefore, when the flush water flows intothe cylinder 14 a from the drive part water supply passage 34 aconnected to the lower portion of the cylinder 14 a, the piston 28 ispushed upward from the lower portion of the cylinder 14 a which is thefirst position H1 (see FIG. 6). Then, when the piston 28 is moved so asto be pushed up to a second position H2 (see FIG. 11) higher than thefirst discharge part 14 m, the water flowing into the cylinder 14 aflows out through the drive part drain passage 34 b from the firstdischarge part 14 m. In other words, the drive part water supply passage34 a and the drive part drain passage 34 b communicate with each othervia the inside of the cylinder 14 a when the piston 28 is moved to thesecond position H2. A discharge part 54 is formed at a front end of thedrive part drain passage 34 b extending from the cylinder 14 a. In thisway, the drive part drain passage 34 b forms a flow channel extending upto the discharge part 54.

As shown in FIG. 6, the cylinder 14 a further includes a through-holeportion 14 f formed in the bottom portion on the first position of thecylinder 14 a and a water storage part 14 j capable of storing the flushwater remaining between a bank portion 14 h (which will be describedbelow) of the through-hole portion 14 f and an inner wall 14 i of thecylinder 14 a.

The through-hole portion 14 f includes a bank portion 14 h that risesupward from a peripheral portion of a through hole formed at the bottomportion of the cylinder 14 a and a flow straightening portion 14 sformed such that a diameter of an inner wall at a top portion issubstantially constant in a moving direction (a height direction in thepresent embodiment) of the rod 32. The bank portion 14 h of the cylinder14 a is formed in an annular shape around the rod 32 in a top view. Theflow straightening portion 14 s is formed extending below from a topportion of the bank portion 14 h by a predetermined distance. The flowstraightening portion 14 s forms a vertical wall extending in thevertical direction. The flow straightening portion 14 s extendssubstantially parallel to an outer wall of the rod 32, and forms a flowchannel having a substantially constant width between the flowstraightening portion 14 s and the rod 32. Thereby, it is possible torestrain turbulence of the flow of the flush water passing between theflow straightening portion 14 s and the rod 32.

The water storage part 14 j forms a water storage portion in thecylinder 14 a at a position lower than the top portion of the bankportion 14 h. The water storage part 14 j is formed in an annular shape.The cylinder 14 a is configured such that the packing 20 is immersed inthe flush water remaining in the water storage part 14 j in the cylinder14 a after the toilet is washed in a state where the lower end of thepacking 20 is in a standby position being the first position H1. Here,the flush water remaining in the cylinder 14 a means flush water(indicated by a residual water level WL3 in FIG. 6) remaining in thecylinder 14 a in a state where the flush water in the cylinder 14 agradually flows out from the through-hole portion 14 f after eachwashing operation and the outflow has been completed. The residual waterlevel WL3 of the remaining flush water is defined by a top portion 14 k(which will be described below) of the bank portion 14 h. The drive partwater supply passage 34 a is formed to be higher than the height of theresidual water level WL3 in a path from the discharge valve hydraulicdrive portion 14 to a vacuum breaker 36. Therefore, the flush water isstored in the cylinder 14 a up to the residual water level WL3 in thestate where the outflow of the flush water from the cylinder 14 a iscompleted. An upper end 20 a of the packing 20 is located at a positionlower than the top portion 14 k of the bank portion 14 h such that thepacking 20 is located in the water storage part 14 j in the state wherethe piston 28 is in the first position H1. When the piston 28 (the lowerend of the piston 28) is in the first position, the packing 20 (thelower end of the packing 20) is also in the first position, so that whenthe piston 28 is in the first position, the packing 20 is described asbeing also in the first position.

As shown in FIG. 6, the cylinder 14 a includes an inlet 14 l (see FIG.4) into which the flush water flows, a first discharge part 14 mprovided separately from the inlet 14 l to cause the flush water todrain, and a second discharge part 14 n provided separately from thefirst discharge part 14 m and formed between the rod 32 and thethrough-hole portion 14 f and between the piston 28 and the through-holeportion 14 f.

The inlet 14 l is connected to the drive part water supply passage 34 a.The inlet 14 l is connected to a lower portion of the water storage part14 j of the cylinder 14 a. The inlet 14 l forms a flow channelcommunicating with a lower side of the piston 28. The first dischargepart 14 m is connected to the drive part drain passage 34 b and forms anoutflow hole to the drive part drain passage 34 b. The second dischargepart 14 n communicates with a space in the reservoir tank 10 on thelower side of the discharge valve hydraulic drive portion 14. The seconddischarge part 14 n is formed between the rod 32 and the through-holeportion 14 f and between the piston 28 and the through-hole portion 14f. The second discharge part 14 n forms a second outflow channel fromthe cylinder 14 a. A minimum cross-sectional area value of the flowchannel of the second discharge part 14 n is smaller than that of theflow channel of the first discharge part 14 m. The minimumcross-sectional area value of the flow channel of the second dischargepart 14 n is equal to or less than half of the minimum cross-sectionalarea value of the flow channel of the first discharge part 14 m, and thesecond discharge part 14 n forms an auxiliary drain flow channelrelative to the first discharge part 14 m.

In the state where the piston 28 is in the first position H1, the seconddischarge part 14 n includes a first flow channel 14 o extendinglaterally between the top portion 14 k of the bank portion 14 h and alower surface portion 28 c, a second flow channel 14 q formed between anouter wall portion 14 p of the bank portion 14 h and the piston 28 andbending downward and extending from the first flow channel 14 o, and athird flow channel 14 r extending downward between the rod 32 and theinner wall of the through-hole portion 14 f in the state where thepiston 28 is in the first position H1. The first flow channel 14 o formsa flow channel with a relatively small gap because the top portion 14 kand the lower surface portion 28 c are substantially in contact witheach other when the piston 28 is in the first position H1. The secondflow channel 14 q and the first flow channel 14 o form a flow channelthat bends in an L shape in a cross-sectional view. Further, the secondflow channel 14 q, the first flow channel 14 o, and the third flowchannel 14 r form a flow channel that bends in a Π shape in across-sectional view. The piston 28 and the cylinder 14 a may beconfigured such that the top portion 14 k and the lower surface portion28 c do not come in contact with each other and the first flow channel14 o of the flow channel with a relatively small gap is formed in thestate where the piston 28 is in the first position H1.

The shape of the second discharge part 14 n changes with the movement ofthe piston 28 in the up-down direction. Therefore, the totalcross-sectional area value and the minimum cross-sectional area value ofthe flow channel in the second discharge part 14 n change with themovement of the piston 28. The second discharge part 14 n is formed suchthat as the piston 28 moves from the first position H1 to the secondposition H2, the total cross-sectional area value and the minimumcross-sectional area value of the flow channel in the second dischargepart 14 n increase and pressure loss of the second discharge part 14 nis reduced. For example, as the piston 28 moves from the first positionH1 to the second position H2, the cross-sectional area of the minimumflow channel in the second discharge part 14 n increases. For example,the cross-sectional area of the minimum flow channel is the minimumcross-sectional area value of the flow channel of the first flow channel14 o between the top portion 14 k of the bank portion 14 h and the lowersurface portion 28 c of the piston 28, and the minimum cross-sectionalarea value of the flow channel of the first flow channel 14 o increasesas the piston 28 ascends. As the piston 28 moves from the first positionH1 to the second position H2, the minimum cross-sectional area value ofthe flow channel of the second flow channel 14 q also increases. Whenthe piston 28 moves from the first position H1 to the second positionH2, the minimum cross-sectional area value of the flow channel of thethird flow channel 14 r is constant.

As will be described below, when an outer diameter of the lower portionof the rod 32 is formed smaller than an outer diameter of the upperportion of the rod 32, the second discharge part 14 n is formed suchthat as piston 28 and the rod 32 ascend, the cross-sectional area of theflow channel of the third flow channel 14 r between the rod 32 and theinner wall of the through-hole portion 14 f, for example, the totalcross-sectional area value and the minimum cross-sectional area valueincrease and the pressure loss of the second discharge part 14 n isreduced. At this time, the minimum cross-sectional area value (across-sectional F1 of the flow channel of the second discharge part 14 nbetween the rod 32 and the inner wall of the through-hole portion 14 fshown in FIG. 7) of the flow channel of the third flow channel 14 r whenthe piston 28 is in the first position H1 is smaller than the minimumcross-sectional area value of the flow channel between the rod 32 andthe inner wall of the through-hole portion 14 f when the piston 28 is inthe second position H2. Further, as the piston 28 ascends, the minimumcross-sectional area value of the flow channel of the first flow channel14 o increases. As the piston 28 ascends, the minimum cross-sectionalarea value of the flow channel of the second flow channel 14 qincreases.

The cylinder 14 a is a substantially tubular member, and is formed in aconical shape in which the inner diameter of the inner wall 14 i of thecylinder 14 a gradually becomes smaller downward. An inner diameter R1(see FIG. 5) of the cylinder 14 a at a portion corresponding to thefirst position H1 of the piston 28 is the minimum inner diameter of thecylinder. The inner diameter R1 of the cylinder 14 a is smaller than aninner diameter R2 (see FIG. 11) of the cylinder 14 a at a portioncorresponding to the second position H2 of the piston 28. The innerdiameter of the cylinder 14 a gradually becomes smaller from the innerdiameter R2 of the second position to inner diameter R1 of the firstposition.

The rod 32 is a rod-shaped member connected to the lower surface of thepiston 28, extends downward from the piston 28 so as to couple thepiston 28 and the discharge valve 12, and extends to protrude downwardfrom the inside of the cylinder 14 a by passing through the through-holeportion 14 f formed in the bottom portion of the cylinder 14 a. Some ofthe flush water flowing into the cylinder 14 a flows out from the seconddischarge part 14 n that forms a gap between the rod 32 and thethrough-hole portion 14 f. The flush water flowing out from the seconddischarge part 14 n flows into the reservoir tank 10. Since the seconddischarge part 14 n is relatively narrow and has a large flow channelresistance, even when the flush water flows out from the seconddischarge part 14 n, the pressure in the cylinder 14 a rises due to theflush water flowing into the cylinder 14 a from the drive part watersupply passage 34 a, and the piston 28 is pushed up against the urgingforce of the spring 48.

As shown in FIG. 6, a center axis G1 of the rod 32 and a center axis G2of the through-hole portion 14 f are located on the same axis as acenter axis G3 of the cylinder 14 a. A maximum outer diameter D1 out ofouter diameters of the entire rod 32 is smaller than a minimum innerdiameter D2 out of inner diameters of the entire through-hole portion 14f. In the present embodiment, the outer diameter of the rod 32 is formedto be substantially constant from an upper portion to a lower portion.The outer diameter of the lower portion of the rod 32 may be smallerthan the outer diameter of the upper portion of the rod 32.

In the present embodiment, the piston 28 is configured to move up anddown in the cylinder 14 a. The first position H1 (see FIGS. 5 and 6) ofthe piston 28 is located below the second position H2 (see FIG. 11). Thesecond position H2 is located above the first discharge part 14 m nearthe center of the cylinder 14 a, and is a position near or above thecenter of the cylinder 14 a, for example. The piston 28 includes a forcereceiving part 28 a that receives the urging force from the spring 48and an upper outer circumference part 28 b formed on the upper side ofthe packing 20.

The force receiving part 28 a is formed outside the bank portion 14 h ina top view. The force receiving part 28 a is formed from a concaveportion having an annular shape. The force receiving part 28 a is incontact with the lower end of the spring 48. The force receiving part 28a is located below the top portion 14 k of the bank portion 14 h in thestate where the piston 28 and the packing 20 are in the first positionH1. A water passageway gap 29, through which the flush water passes, isformed between the upper outer circumference part 28 b and the innerwall 14 i of the cylinder 14 a. The water passageway gap 29 is formed inan annular shape with a substantially uniform width over the entirecircumference. Since the cylinder 14 a is formed in the conical shape,the water passageway gap 29 gradually becomes smaller from the upperside to the lower side of the cylinder 14 a as the piston 28 moves fromthe upper side to the lower side of the cylinder 14 a.

As shown in FIG. 6, the packing 20 is attached to the piston 28 and hasa function of ensuring watertightness of the seal between the inner wallsurface of the cylinder 14 a and the piston 28. The packing 20 is aso-called U packing having a U-shaped cross section. The packing 20 isdisposed such that an open side having a U shape is directed downwardand the cross section is an inverted U shape. When the piston 28 is inthe standby position of the first position, the lower end 20 b of thepacking 20 is located above the full water level WL of the reservoirtank 10. The packing 20 is an elastic member formed of rubber. Since thepacking 20 slides with respect to the inner wall surface of the cylinder14 a together with the piston 28, as long as the packing 20 has acertain degree of sealing function capable of restraining the flushwater from leaking, it is no matter the flush water slightly leaksbetween the packing 20 and the inner wall surface of the cylinder 14 a.The packing 20 may be a lip packing (for example, L packing or V packingamong the lip packing) having a sealing portion formed in a lip shape,or a squeeze packing (for example, O-ring or X-ring among the squeezepacking) for sealing by giving a squeeze.

The first control valve 16 and the second control valve 22 will bedescribed below with reference to FIG. 2.

The first control valve 16 is configured to control water supply to thedischarge valve hydraulic drive portion 14 and to supply and stop thewater supply to the discharge part 54 based on the operation of theelectromagnetic valve 18. In other words, the first control valve 16includes a main valve body 16 a, a main valve port 16 b opened andclosed by the main valve body 16 a, a pressure chamber 16 c configuredto move the main valve body 16 a, and a pilot valve 16 d configured toswitch the pressure in the pressure chamber 16 c.

The main valve body 16 a is configured to open and close the main valveport 16 b of the first control valve 16. When the main valve port 16 bis opened, the tap water supplied from the water supply pipe 38 flowsinto the discharge valve hydraulic drive portion 14. The pressurechamber 16 c is provided in a housing of the first control valve 16 tobe adjacent to the main valve body 16 a. The pressure chamber 16 c isconfigured such that some of the tap water supplied from the watersupply pipe 38 flows into and the internal pressure rises. When thepressure in the pressure chamber 16 c rises, the main valve body 16 amoves toward the main valve port 16 b and the main valve port 16 b isclosed.

The pilot valve 16 d is configured to open and close a pilot valve port(not shown) provided in the pressure chamber 16 c. When the pilot valveport (not shown) is opened by the pilot valve, the water in the pressurechamber 16 c flows out and the internal pressure drops. When thepressure in the pressure chamber 16 c drops, the main valve body 16 a isseparated from the main valve port 16 b, and the first control valve 16is opened. Further, when the pilot valve 16 d is closed, the pressure inthe pressure chamber 16 c rises, and the first control valve 16 isclosed.

The pilot valve 16 d is moved by the electromagnetic valve 18 attachedto the pilot valve 16 d to open and close the pilot valve port (notshown). The electromagnetic valve 18 is electrically connected to acontroller 40, and causes the pilot valve 16 d to move based on acommand signal from the controller 40. Specifically, the controller 40receives signals from the remote controller 6 and the human sensor 8,and the controller 40 sends an electric signal to the electromagneticvalve 18 and causes the electromagnetic valve 18 to be operated.

In addition, the vacuum breaker 36 is provided in the drive part watersupply passage 34 a located between the first control valve 16 and thedischarge valve hydraulic drive portion 14. When the pressure on thefirst control valve 16 becomes negative, the vacuum breaker 36 restrainsbackflow of water to the first control valve 16.

Next, the second control valve 22 is configured to supply and stop thewater supply to the reservoir tank 10 based on the operation of theelectromagnetic valve 24. The second control valve 22 is connected tothe water supply pipe 38 via the first control valve 16, but the tapwater supplied from the water supply pipe 38 always flows into thesecond control valve 22 in spite of opening and closing of the firstcontrol valve 16. Further, the second control valve 22 includes a mainvalve body 22 a, a pressure chamber 22 b, and a pilot valve 22 c, andthe pilot valve 22 c is opened and closed by the electromagnetic valve24. When the pilot valve 22 c is opened by the electromagnetic valve 24,the main valve body 22 a of the second control valve 22 is opened, andthe tap water flowing in from the water supply pipe 38 is supplied tothe reservoir tank 10 or the overflow pipe 10 b. The electromagneticvalve 24 is electrically connected to the controller 40, and the pilotvalve 22 c moves based on the command signal from the controller 40.Specifically, based on the operation of the remote controller 6, thecontroller 40 sends an electric signal to the electromagnetic valve 24and causes the electromagnetic valve 24 to be operated. Theelectromagnetic valve 24 may not be provided. When the electromagneticvalve 24 is not provided, the pilot valve 22 c is controlled by a floatswitch 42 as will be described below.

On the other hand, the float switch 42 is connected to the pilot valve22 c. The float switch 42 is configured to control the pilot valve 22 cbased on the water level in the reservoir tank 10 and to open and closea pilot valve port (not shown). In other words, the float switch 42sends a signal to the pilot valve 22 c to close the pilot valve port(not shown) when the water level in the reservoir tank 10 reaches apredetermined water level. In other words, the float switch 42 isconfigured to set the water storage level in the reservoir tank 10 to apredetermined full water level WL which is a stopped water level. Thefloat switch 42 is disposed in the reservoir tank 10 and is configuredto stop the water supply from the first control valve 16 to thedischarge valve hydraulic drive portion 14 when the water level of thereservoir tank 10 rises to the full water level WL. The float switch 42can be replaced with a ball tap mechanism. The ball tap mechanismincludes a float for ball tap that moves up and down according to thewater level and a support arm connected to the float for ball tap andacting on the pilot valve 22 c. In the ball tap mechanism, when thewater level of the reservoir tank 10 rises to the full water level WL,the float for ball tap rises and the support arm connected to the floatfor ball tap rotates upward to mechanically close the pilot valve port(not shown) of the pilot valve 22 c. In the ball tap mechanism, when thewater level of the reservoir tank 10 drops below the full water levelWL, the float for ball tap descends and the support arm connected to thefloat for ball tap rotates downward to mechanically open the pilot valveport (not shown) of the pilot valve 22 c.

In addition, a water supply passage 50 extending from the second controlvalve 22 is provided with a water supply passage branch portion 50 a.One water supply passage 50 branched at the water supply passage branchportion 50 a allows the water to flow out into the reservoir tank 10,and the other water supply passage 50 allows the water to flow out intothe overflow pipe 10 b. Therefore, some of the flush water supplied fromthe second control valve 22 is discharged to the flush toilet main body2 through the overflow pipe 10 b, and the remaining flush water isstored in the reservoir tank 10.

Further, a vacuum breaker 44 is provided in the water supply passage 50.When the pressure on the second control valve 22 becomes negative, thevacuum breaker 44 restrains backflow of the water to the second controlvalve 22.

The water supplied from the tap water is supplied to the first controlvalve 16 and the second control valve 22 via a stop cock 38 a disposedoutside the reservoir tank 10 and a fixed flow valve 38 b disposed inthe reservoir tank 10 on the downstream side of the stop cock 38 a. Thestop cock 38 a is provided to stop the supply of water to the flushwater tank apparatus 4 at the time of maintenance, and is usually usedin an opened state. The fixed flow valve 38 b is provided to allow thewater supplied from the tap water to flow into the first control valve16 and the second control valve 22 at a predetermined flow rate, and isconfigured to be supplied with the water at a constant flow rateregardless of the installation environment of the flush toilet apparatus1.

The controller 40 has a built-in CPU and a memory, and controlsconnected apparatus so as to execute a large washing mode and a smallwashing mode, which will be described below, based on a predeterminedcontrol program recorded in the memory. The controller 40 iselectrically connected to the remote controller 6, the human sensor 8,the electromagnetic valve 18, and the electromagnetic valve 24.

The float apparatus 26 will be described below. The float apparatus 26is provided near the discharge valve 12. The float apparatus 26 isconfigured such that the valve shaft frame body 12 a is lifted by apredetermined distance and the valve shaft frame body 12 a of thedischarge valve 12 descends after the valve shaft frame body 12 a isdetached by the clutch mechanism 30 to delay the closing of the waterdischarge opening 10 a. Specifically, the float apparatus 26 includes afloat part 26 a and an engaging part 26 b interlocking with the floatpart 26 a. On the other hand, a holding claw 12 g is formed at aproximal end of the valve shaft frame body 12 a of the discharge valve12 to engage with the engaging part 26 b.

The engaging part 26 b is configured to engage with the holding claw 12g of the valve shaft frame body 12 a that descends after being detachedby the clutch mechanism 30 and to restrain the valve shaft frame body 12a and the discharge valve 12 from being seated on the water dischargeopening 10 a by descending. Next, when the float part 26 a descends asthe water level in the reservoir tank 10 drops and the water level inthe reservoir tank 10 drops to a predetermined water level, the floatpart 26 a rotates the engaging part 26 b and the engagement of theengaging part 26 b and the holding claw 12 g is released. When theengagement is released, the valve shaft frame body 12 a and thedischarge valve 12 descend, and are seated on the water dischargeopening 10 a. Thus, the closing of the discharge valve 12 is delayed,and an appropriate amount of flush water is discharged from the waterdischarge opening 10 a.

A configuration and an operation of the clutch mechanism 30 will bedescribed below with reference to FIGS. 8 to 13.

As shown in FIG. 8, the clutch mechanism 30 is provided at the lower endof the rod 32 extending downward from the discharge valve hydraulicdrive portion 14 and is configured to couple and release the lower endof the rod 32 and the upper end of the valve shaft frame body 12 a ofthe discharge valve 12. The clutch mechanism 30 includes a movable body60 to uncouple the discharge valve 12 and the discharge valve hydraulicdrive portion 14, a thin portion 33 that has an outer shape of the rod32 formed thinner than the upper portion on the distal end of the rod32, a pull-up part 35 whose diameter expands again at the lower end ofthe thin portion 33 of the rod 32, and a regulation part 37 (see FIG. 5)that hangs downward from the bottom surface of the cylinder 14 a on theoutside of the rod 32.

The movable body 60 is provided on the valve shaft frame body 12 a ofthe discharge valve 12. The movable body 60 is rotatably attached to thesupport portion 12 d of the valve shaft frame body 12 a. The movablebody 60 forms a movable mechanism that operates on the discharge valveside in the state of being attached to the support portion 12 d. Themovable body 60 is configured to switch between an engaging side postureand a non-engaging side posture, which will be described below, by arotational operation.

The movable body 60 includes a base plate 62 extending laterally, an arm64 rising vertically from both sides of the base plate, a rotary shaft66 that is a center of the rotational operation of the movable body 60,and a contact portion 68 coming in contact with the rod 32 of thedischarge valve hydraulic drive portion 14 when the rod 32 of thedischarge valve hydraulic drive portion 14 attempts to pull up thedischarge valve 12.

The clutch mechanism 30 is configured in which the pull-up part 35 ofthe rod 32 is located below the contact portion 68 of the movable body60 in the standby state. The clutch mechanism 30 is configured in whichthe movable body 60 comes in contact with the pull-up part 35 of the rod32 and pulls up the valve shaft frame body 12 a of the discharge valve12 when the rod 32 is pulled up from the standby state. Further, asshown in FIG. 10, when the rod 32 is pulled up to a predeterminedheight, the base plate 62 of the clutch mechanism 30 hits the regulationpart 37, the movable body 60 rotates, and the clutch mechanism 30 isdisengaged. As shown in FIGS. 12 and 13, after the movable body 60 andthe discharge valve 12 descend, the rod 32 also descends to return tothe standby state of the clutch mechanism 30.

A description will be given below with reference to FIGS. 2 and 6 withrespect to the flush water tank apparatus 4 according to the firstembodiment of the present invention and a series washing operations ofthe flush toilet apparatus 1 including the flush water tank apparatus 4.

First, in the standby state of toilet washing shown in FIG. 2, the waterlevel in the reservoir tank 10 is at a predetermined full water levelWL, and in this state, both the first control valve 16 and the secondcontrol valve 22 are closed. Further, the float apparatus 26 is in astandby state. Next, when a user pushes a washing button of the remotecontroller 6, the remote controller 6 transmits an instruction signalfor the toilet washing to the controller 40. In the flush toiletapparatus 1 of the present embodiment, even when a predetermined timeelapses without pushing the washing button of the remote controller 6after the human sensor 8 detects that the user leaves from the toilet,the instruction signal for the toilet washing is transmitted to thecontroller 40.

As shown in FIG. 6, in the standby state, the piston 28 of the dischargevalve hydraulic drive portion 14 is at the first position H1 in thecylinder 14 a. The first position H1 of the piston 28 is a lower limitposition in a movable range. The piston 28 is stopped in the cylinder 14a. At this time, the lower end 20 b of the packing 20 is located abovethe full water level WL of the reservoir tank 10. Therefore, the packing20 is disposed in a region to be directly supplied with the flush waterfrom the tap water so as not to be immersed in the flush water stored inthe reservoir tank 10 in which what chemical for the toilet washing suchas chlorine is charged by the user is unknown. Therefore, it is possibleto restrain the packing 20 from being deteriorated by being immersed insuch a chemical.

On the other hand, in the standby state, the residual water level WL3indicating the remaining flush water is formed in the water storage part14 j in the cylinder 14 a. In the state where the piston 28 is in thestandby position being the first position, the packing 20 is immersedand submerged in the flush water remaining in the water storage part 14j in the cylinder 14 a. Thus, it is possible to restrain the packing 20from drying until being mostly dried, and to restrain the formation ofscale (precipitate) in the packing 20 from the tap water by repetitionof wetting and drying with the flush water.

In addition, the packing 20 is immersed in the flush water directlysupplied from the tap water, unlike the flush water stored in thereservoir tank 10 in which what washing agent for the toilet washing ischarged by the user is unknown, thereby the deterioration of the packing20 due to chlorine such as a toilet washing agent can also berestrained.

A deformation amount of the packing 20 in the state where the piston 28is at the first position H1 is a maximum deformation amount indeformation amounts of the elastic member at respective positions whilethe piston 28 moves from the first position H1 to the second positionH2. The deformation amount of the packing 20 is determined by an openingwidth of the U-shaped packing. For example, an opening width W1 (seeFIG. 6) of the packing 20 in the state where the piston 28 is at thefirst position H1 is smaller than an opening width W2 (see FIG. 11) ofthe packing 20 in the state where the piston 28 is at the secondposition H2. The opening width W2 of the packing 20 is smaller than anopening width W3 (not shown) of the packing 20 in an initial state wherethe packing 20 is not housed in the cylinder 14 a. Further, as thepiston 28 moves from the first position H1 to the second position H2,the opening width of the packing 20 gradually increases. As describedabove, the deformation amount (W3−W1) of the packing 20 in the statewhere the piston 28 is at the first position H1 is larger than thedeformation amount (W3−W2) of the packing 20 in the state where thepiston 28 is at the second position H2.

In the standby state where the piston 28 is at the first position H1,the spring 48 is in the most extended state, and the top portion 14 k ofthe bank portion 14 h is in contact with the lower surface portion 28 c.The piston 28 is urged toward the side of the first position by thespring 48, and is stopped in a state of being in contact with the topportion 14 k.

In the standby state where the piston 28 is at the first position H1,the cross-sectional area of the flow channel in the second dischargepart 14 n is determined by the cross-sectional area of the flow channelbetween the rod 32 and the through-hole portion 14 f and thecross-sectional area of the flow channel between the piston 28 and thethrough-hole portion 14 f. The cross-sectional area of the minimum flowchannel in the second discharge part 14 n is the cross-sectional area ofthe first flow channel 14 o, and since the top portion 14 k and thelower surface portion 28 c are substantially in contact with each other,the pressure loss of the second discharge part 14 n becomes larger.

Next, upon receiving the instruction signal for the toilet washing, thecontroller 40 allows the electromagnetic valve 18 (FIG. 2) provided inthe first control valve 16 to operate, and allows the pilot valve 16 don the electromagnetic valve side to be separated from the pilot valveport. Thus, the pressure in the pressure chamber 16 c drops, the mainvalve body 16 a is separated from the main valve port 16 b, and the mainvalve port 16 b is opened. When the first control valve 16 is opened,the flush water flowing in from the water supply pipe 38 is supplied tothe discharge valve hydraulic drive portion 14 via the first controlvalve 16. Thereby, the piston 28 of the discharge valve hydraulic driveportion 14 is pushed up, the discharge valve 12 is pulled up via the rod32, and the flush water in the reservoir tank 10 is discharged from thewater discharge opening 10 a to the flush toilet main body 2.

When the discharge valve 12 is pulled up, the holding claw 12 g providedon the valve shaft frame body 12 a of the discharge valve 12 pushes upand rotates the engaging part 26 b of the float apparatus 26, and theholding claw 12 g ascends beyond the engaging part 26 b.

After the standby state of the piston 28, for example, when the piston28 ascends, the flush water flowing into a lower chamber 14 b, which islocated below the piston 28, of the cylinder 14 a is retained in thelower chamber 14 b by the packing 20 having a sealing function togenerate a force that raises the piston 28. On the other hand, since thepiston 28 and the packing 20 move up and down in the cylinder 14 a, someof the flush water flowing into the lower chamber 14 b passes through aspace between the packing 20 and the inner wall 14 i of the cylinder 14a and leaks into an upper chamber 14 e located above the piston 28. Atthis time, since the water passageway gap 29 is formed between the upperouter circumference part 28 b and the inner wall 14 i, the upper side ofthe packing 20 can be more easily immersed in the flush water. Further,the entire upper side of the packing 20 can be easily immersed in theflush water. Therefore, the entire packing 20 including the upper sideof the packing 20 is immersed in the flush water. As will be describedbelow, even at the time of descending of the piston 28 after the clutchmechanism 30 is disengaged and in the standby state, the upper side ofthe packing 20 is easily immersed, by the water passageway gap 29, inthe flush water flowing into the upper chamber 14 e.

Next, as shown in FIG. 10, when the discharge valve 12 is further pulledup, the clutch mechanism 30 is disengaged. In other words, when thedischarge valve 12 reaches a predetermined height, the base plate 62 ofthe clutch mechanism 30 hits the regulation part 37, and the clutchmechanism 30 is disengaged.

Next, as shown in FIG. 11, when the clutch mechanism 30 is disengaged,the discharge valve 12 starts to descend toward the water dischargeopening 10 a due to its own weight. The holding claw 12 g of thedescending discharge valve 12 engages with the engaging part 26 b of thefloat apparatus 26, and the discharge valve 12 is held at apredetermined height by the engaging part 26 b. When the discharge valve12 is held by the engaging part 26 b, the water discharge opening 10 ais maintained in an open state, and flush water in the reservoir tank 10is maintained to be discharged to the flush toilet main body 2. At thistime, the pilot valve 16 d is still in the open state, and the flushwater flowing in from the water supply pipe 38 is supplied to thedischarge valve hydraulic drive portion 14 via the first control valve16.

When the piston 28 ascends up to the second position higher than thefirst discharge part 14 m, the drive part water supply passage 34 a andthe drive part drain passage 34 b communicate with each other via theinside of the cylinder 14 a, and the flush water is discharged into thereservoir tank 10 from the discharge part 54.

At this time, the water passageway gap 29 between the upper outercircumference part 28 b and the inner wall 14 i is formed to becomesmaller from the upper side to the lower side of the cylinder 14 a. Inother words, the water passageway gap 29 is formed relatively largeabove the cylinder 14 a.

In addition, when the piston 28 is located above the cylinder 14 a, theflush water is more likely to leak from the space between the packing 20and the inner wall 14 i to the upper chamber 14 e, as compared with thecase where the piston 28 is located below the cylinder 14 a. Thus, someof the flush water leaks from the lower chamber 14 b to the upperchamber 14 e on the upper side of the packing 20. Therefore, the entirepacking 20 including the upper side of the packing 20 is immersed in theflush water. Further, the opening width of the packing 20 in the statewhere the piston 28 is at the second position H2 is the opening widthW2.

In the second discharge part 14 n in the state where the piston 28 is atthe second position H2, the top portion 14 k and the lower surfaceportion 28 c are separated from each other, the minimum cross-sectionalarea value of the flow channel of the first flow channel 14 o increases,and the minimum cross-sectional area value of the flow channel of thesecond flow channel 14 q also increases. On the other hand, the minimumcross-sectional area value of the flow channel of the third flow channel14 r remains constant. In this way, as the piston 28 ascends toward thesecond position H2, the top portion 14 k and the lower surface portion28 c are separated from each other, the cross-sectional areas of theflow channels of the first flow channel 14 o and the second flow channel14 q increase, the total cross-sectional area value and the minimumcross-sectional area value of the flow channel in the second dischargepart 14 n increase, and the pressure loss of the second discharge part14 n is reduced. In the state where the piston 28 is at the secondposition H2, the clutch mechanism 30 is disengaged. When the clutchmechanism 30 is disengaged as described above, the minimumcross-sectional area value of the flow channel of the second dischargepart 14 n is a maximum cross-sectional area value of the flow channelwithin the range of change from the first position H1 to the secondposition H2 of the piston 28. Therefore, when the clutch mechanism 30 isdisengaged, the pressure loss of the second discharge part 14 n is aminimum pressure loss in the range of change in corresponding pressureloss from the first position H1 to the second position H2 of the piston28.

Next, when the water level in the reservoir tank 10 drops, the floatswitch 42 for detecting the water level in the reservoir tank 10 isturned off. When the float switch 42 is turned off, the pilot valve 22 cprovided in the second control valve 22 is opened. Therefore, the flushwater is supplied from the second control valve 22 into the reservoirtank 10 via the water supply passage 50. The controller 40 allows theelectromagnetic valve 18 to be closed when a predetermined time haselapsed from the opening of the electromagnetic valve 18, and allows thepilot valve 16 d on the electromagnetic valve side to be closed. Themain valve body 16 a of the first control valve 16 is closed when thepilot valve 16 d is closed. Even after the pilot valve 16 d on theelectromagnetic valve side is closed, the open state of the secondcontrol valve 22 is maintained and the water supply to the reservoirtank 10 is continued. Since the first control valve 16 is closed, thesupply of the flush water to the discharge valve hydraulic drive portion14 and the discharge part 54 is stopped.

In addition, when the water level in the reservoir tank 10 drops up tothe predetermined water level WL1, the float part 26 a of the floatapparatus 26 descends, which moves the engaging part 26 b. Thus, theengagement between the valve shaft frame body 12 a and the engaging part26 b is released, and the valve shaft frame body 12 a and the dischargevalve 12 start to descend again.

Thereby, the discharge valve 12 is seated on the water discharge opening10 a, and the water discharge opening 10 a is closed. After the firstcontrol valve 16 is closed and the water supply to the discharge valvehydraulic drive portion 14 is stopped, the flush water in the cylinder14 a of the discharge valve hydraulic drive portion 14 gradually flowsout from the second discharge part 14 n, the piston 28 is pushed down bythe urging force of the spring 48, and the rod 32 is lowered at the sametime.

Thus, as shown in FIG. 13, the distal end 32 a of the rod 32 comes intocontact with the base plate 62, and the movable body 60 is sandwichedand stopped between the valve shaft frame body 12 a and the rod 32 andreturns to the standby state (see FIG. 5) before the start of the toiletwashing. In the state where the piston 28 returns to the standby stateof the first position H1 again, some of the flush water leaks into theupper chamber 14 e on the upper side of the piston 28. Since the waterpassageway gap 29 is formed to become smaller from the upper side to thelower side of the cylinder 14 a, when the piston 28 is at the firstposition H1, the flush water on the upper side of the packing 20 hardlypasses downward from the water passageway gap 29. Thus, the flush watercan be easily maintained in upper chamber 14 e, and the upper side ofthe packing 20 can be more easily immersed in the flush water.Therefore, the entire packing 20 including the upper side of the packing20 is immersed in the flush water.

Since the float switch 42 is still in the off state, the open state ofthe second control valve 22 is maintained, and the water supply to thereservoir tank 10 is continued. The flush water supplied through thewater supply passage 50 reaches the water supply passage branch portion50 a, some of the flush water branched at the water supply passagebranch portion 50 a flows into the overflow pipe 10 b, and the remainingflush water is stored in the reservoir tank 10. The flush water flowinginto the overflow pipe 10 b flows into the flush toilet main body 2, andis used to refill the bowl 2 a. On the other hand, the water level inthe reservoir tank 10 rises due to the flush water flowing into thereservoir tank 10 in the state where the discharge valve 12 is closed.

When the water level in the reservoir tank 10 rises to the predeterminedfull water level WL, the float switch 42 is turned on. When the floatswitch 42 is turned on, the pilot valve 22 c on the float switch side isclosed. Thereby, since the pilot valve 22 c is closed, the pressure inthe pressure chamber 22 b increases, the main valve body 22 a of thesecond control valve 22 is closed, and the water supply is stopped.Therefore, as shown in FIG. 2, the apparatus in the reservoir tank 10returns to the standby state.

According to the flush water tank apparatus 4 of the first embodiment ofthe present invention described above, the cylinder 14 a includes theinlet 14 l into which the flush water flows, the first discharge part 14m provided separately from the inlet 14 l to cause the flush water todrain, and the second discharge part 14 n provided separately from thefirst discharge part 14 m and formed between the rod 32 and thethrough-hole portion 14 f. Thereby, when the water supply pressure ofthe flush water to the cylinder 14 a suddenly fluctuates, for example,suddenly rises in the state where the flow channel is not communicatedor is communicated from the inlet 14 l to the first discharge part 14 min the cylinder 14 a, the second discharge part 14 n can soften theimpact of the sudden fluctuation in the pressure of the flush water, thepiston 28 can buffer the impact applied from the flush water, and theunstable operation of the piston 28 can be restrained. Further, when thewater supply pressure of the flush water to the cylinder 14 a suddenlyfluctuates, for example, suddenly rises in the state where the flowchannel is communicated from the inlet 14 l to the first discharge part14 m in the cylinder 14 a, the second discharge part 14 n can soften theimpact of the sudden fluctuation in the pressure of the flush water, andthus can restrain the fluctuation in the pressure of the flush waterdrained from the first discharge part 14 m. Thereby, it is possible torestrain the flush water drained to the downstream side of the firstdischarge part 14 m from becoming unstable. For example, even when theflush water is used on the downstream side of the first discharge part14 m, it is possible to restrain the supply of the flush water frombecoming unstable.

Further, according to the flush water tank apparatus 4 of the firstembodiment of the present invention, the deformation amount of thepacking 20 in the state where the piston 28 is at the first position H1is the maximum deformation amount in deformation amounts of the packing20 at respective positions while the piston 28 moves from the firstposition H1 to the second position H2. Thereby, when the piston 28 islocated at the first position H1, which is the position at the start ofthe water supply that is most susceptible to fluctuations in the watersupply pressure of the flush water due to the water supply, thedeformation amount of the packing 20 is the maximum deformation amount,and the force supporting the piston 28 is also maximum. Thus, it ispossible to restrain the piston 28 from tilting due to the fluctuationof the water supply pressure and to restrain the operation of the piston28 from becoming unstable.

Further, according to the flush water tank apparatus 4 of the firstembodiment of the present invention, the inner diameter of the cylinder14 a at the portion corresponding to the first position H1 of the piston28 is the minimum inner diameter of the cylinder 14 a. Thereby, when thepiston 28 is located at the first position H1, the deformation amount ofthe packing 20 is the maximum deformation amount, and the forcesupporting the piston 28 is also the maximum supporting force amongsupporting forces at respective positions, so that it is possible torestrain the piston 28 from tilting due to the fluctuations of the watersupply pressure and to restrain the operation of the piston 28 frombecoming unstable with a relatively simple configuration.

Further, according to the flush water tank apparatus 4 of the firstembodiment of the present invention, the discharge valve hydraulic driveportion 14 further includes the spring 48 provided in the cylinder 14 aand urging the piston 28 toward the side of the first position H1.Thereby, the spring 48 enables the buffering operation of the piston 28and can restrain the unstable operation of the piston 28. Further, evenwhen the force stabilizing the piston 28 is reduced in the state wherethe piston 28 is at the first position H1 and the spring 48 isstretched, the deformation amount of the packing 20 is the maximumdeformation amount among the deformation amounts at respectivepositions, and the force supporting the piston 28 is also the maximumsupporting force among supporting forces at respective positions, sothat the reduction in the stabilizing force of the spring 48 can becompensated by the supporting force of the packing 20 and the operationof the piston 28 can be stabilized.

Further, according to the flush water tank apparatus 4 of the firstembodiment of the present invention, as the piston 28 moves from thefirst position H1 to the second position H2, the cross-sectional area ofthe flow channel in the second discharge part 14 n increases and thepressure loss of the second discharge part 14 n is reduced. Thereby, thepressure loss of the second discharge part 14 n is set to the maximum inthe initial stage when the supply of the flush water into the cylinder14 a is started, the water supply pressure of the flush water isdifficult to escape toward the side of the second discharge part 14 n,and the water supply pressure of the flush water can be effectively usedto raise the piston 28.

Further, according to the flush water tank apparatus 4 of the firstembodiment of the present invention, the second discharge part 14 n isformed such that as the piston 28 moves from the first position H1 tothe second position H2, the cross-sectional area of the flow channel ofthe second discharge part 14 n between the rod 32 and the inner wall ofthe through-hole portion 14 f increases and the pressure loss of thesecond discharge part 14 n is reduced. Thereby, the pressure loss of thesecond discharge part 14 n is set to the maximum in the initial stagewhen the supply of the flush water into the cylinder 14 a, in which thepiston 28 is at the first position H1, is started, the water supplypressure of the flush water is difficult to escape toward the side ofthe second discharge part 14 n, and the water supply pressure of theflush water can be effectively used to raise the piston 28. Further,when the piston 28 reaches the second position H2, the pressure loss ofthe second discharge part 14 n is set to be relatively low, the flushwater in the cylinder 14 a can easily flow out from the second dischargepart 14 n, and the impact generated in the flush water in the cylinder14 a can be softened.

Further, according to the flush water tank apparatus 4 of the firstembodiment of the present invention, in the state where the piston 28 isin the first position H1, the second discharge part 14 n includes thefirst flow channel 14 o extending laterally between the top portion 14 kof the bank portion 14 h and the piston 28, and the second flow channel14 q formed between an outer wall portion 14 p of the bank portion 14 hand the piston 28 and bending downward and extending from the first flowchannel 14 o. Thereby, the pressure loss of the second discharge part 14n is set to the maximum in the initial stage when the supply of theflush water into the cylinder 14 a, in which the piston 28 is at thefirst position H1, is started, the water supply pressure of the flushwater is difficult to escape toward the side of the second dischargepart 14 n, and the water supply pressure of the flush water can beeffectively used to raise the piston 28.

Further, according to the flush water tank apparatus 4 of the firstembodiment of the present invention, the impact is transmitted to thepiston 28 through the rod 32 from the clutch mechanism 30 when theclutch mechanism 30 is disengaged. At this time, the cross-sectionalarea of the flow channel of the second discharge part 14 n is themaximum cross-sectional area among the cross-sectional areas of the flowchannel of the second discharge part 14 n at respective positions whilethe piston 28 moves from the first position H1 to the second positionH2, and the piston 28 is easy to move. Thus, the impact transmitted tothe piston 28 can be easily released, the operation of the piston 28 canbe stabilized, and the generation of abnormal noise due to the impacttransmitted to the piston 28 can be restrained.

Further, according to the flush water tank apparatus 4 of the firstembodiment of the present invention, the center axis G1 of the rod 32and the center axis G2 of the through-hole portion 14 f are located onthe same axis as the center axis G3 of the cylinder 14 a. Thereby, aforce is applied to the piston 28 in the cylinder 14 a relativelyuniformly in a circumferential direction, and the rod 32 can berestrained from tilting with respect to the center axis G3 of thecylinder 14 a when the rod 32 moves up and down. At the same time, evenwhen the piston 28 buffers the impact applied from the flush water, thetilting of the rod 32 can be restrained.

Further, according to the flush water tank apparatus 4 of the firstembodiment of the present invention, the through-hole portion 14 ffurther includes the flow straightening portion 14 s formed such thatthe diameter of the inner wall at the top portion 14 k is constant inthe moving direction of the rod 32. Thus, the turbulence of the flow ofthe flush water passing through the flow straightening portion 14 s canbe restrained, the flush water can be drained relatively uniformly inthe circumferential direction, and the rod 32 can be restrained fromtilting.

Further, according to the flush water tank apparatus 4 of the firstembodiment of the present invention, the maximum outer diameter of therod 32 is smaller than the minimum inner diameter of the through-holeportion 14 f. Thereby, the rod 32 can be inserted into the through-holeportion 14 f from the upper side of the through-hole portion 14 f toassemble the discharge valve hydraulic drive portion 14. Further, it ispossible to restrain the flush water flowing out from the seconddischarge part 14 n formed between the rod 32 and the through-holeportion 14 f from colliding with the outside of the rod 32 after theoutflow and to restrain the rod 32 from deviating from the originallyplanned center axis. At the same time, it is possible to restrain theflush water from colliding with other apparatus and destabilizing theoperation of the other apparatus due to the scattering of the flushwater colliding with the outside of the rod 32.

Further, the first embodiment of the present invention relates to theflush toilet apparatus 1 including the flush toilet main body 2 and theflush water tank apparatus 4 which can restrain the operation of thepiston 28 from becoming unstable and can restrain the fluctuations inthe pressure of the flush water drained from the first discharge part 14m provided separately from the inlet 14 l.

According to the flush water tank apparatus 4 of the first embodiment ofthe present invention described above, when the piston 28 is at thefirst position, the lower end of the packing 20 is located above thefull water level WL of the reservoir tank 10. Thereby, it is possible torestrain the packing 20 from being immersed in the flush water stored inthe reservoir tank 10 in which what chemical for the toilet washing suchas chlorine is charged by the user is unknown, and to restrain thepacking 20 from being deteriorated by the immersion. Therefore, it ispossible to reduce the possibility that the discharge valve hydraulicdrive portion 14 malfunctions.

Further, according to the flush water tank apparatus 4 of the firstembodiment of the present invention, the cylinder 14 a of the dischargevalve hydraulic drive portion 14 is configured such that the packing 20is immersed in the flush water remaining in the cylinder 14 a in thestate where the piston 28 is at the first position H1. Thereby, it ispossible to restrain the formation of scale (precipitate) in the packing20 from the tap water by repetition of wetting and drying with the flushwater and to restrain the deterioration of the packing 20 by theimmersion in the flush water stored in the reservoir tank 10. Therefore,the deterioration of the packing 20 can be restrained while theformation of the scale on the packing 20 can be restrained. On the otherhand, when the packing 20 is to be submerged in the flush water in thereservoir tank 10 in order to restrain the formation of the scale, it isnecessary to dispose the packing 20 on the bottom surface side below thedead water level which is the lower limit of the water level of thereservoir tank 10 in order to submerge the packing 20 regardless of thechange in the water level of the flush water in the reservoir tank 10,and the degree of freedom in arrangement of the piston 28 and thecylinder 14 a accompanied by the arrangement of the packing 20. Thereby,according to the first embodiment of the present invention, it ispossible to restrain the occurrence of such a problem that the degree offreedom in arrangement is impaired while restraining the formation ofthe scale, and the packing 20 can be disposed relatively freely.

Further, according to the flush water tank apparatus 4 of the firstembodiment of the present invention, the upper end of the packing 20 islocated at the position lower than the top portion 14 k of the bankportion 14 h such that the packing 20 is located in the water storagepart 14 j in the state where the piston 28 is at the first position H1.Therefore, with a relatively simple configuration, it is possible torestrain the formation of scale (precipitate) in the packing 20 from thetap water by repetition of wetting and drying with the flush water andto restrain the deterioration of the packing 20 by the immersion in theflush water stored in the reservoir tank 10. Therefore, thedeterioration of the packing 20 can be restrained while the formation ofthe scale on the packing 20 can be restrained.

Further, according to the flush water tank apparatus 4 of the firstembodiment of the present invention, the top portion 14 k of the bankportion 14 h is in contact with the lower surface portion 28 c of thepiston 28 in the state where the piston 28 is at the first position H1.Thereby, the outflow of the flush water in the water storage part 14 jcan be restrained, and the state where the packing 20 is immersed in theflush water can be easily maintained.

Further, according to the flush water tank apparatus 4 of the firstembodiment of the present invention, the bank portion 14 h of thecylinder 14 a is formed in the annular shape around the rod 32 in a topview and the top portion 14 k of the bank portion 14 h is in contactwith the lower surface portion 28 c of the piston 28 in the state wherethe piston 28 is at the first position H1. Thereby, the outflow of theflush water in the water storage part 14 j can be further restrained,and the state where the packing 20 is immersed in the flush water can bemore easily maintained.

Further, according to the flush water tank apparatus 4 of the firstembodiment of the present invention, the discharge valve hydraulic driveportion 14 further includes the spring 48 that is provided in thecylinder 14 a and urges the piston 28 toward the side of the firstposition H1. In the state where the piston 28 is at the first positionH1, the contact between the top portion 14 k of the bank portion 14 hand the lower surface portion 28 c of the piston 28 can be more easilymaintained. Thereby, it is possible to further restrain the outflow ofthe flush water in the water storage part 14 j and to maintain the statewhere the packing 20 is immersed in the flush water more easily. Inaddition, the piston 28 of the discharge valve hydraulic drive portion14 includes the force receiving part 28 a that receives the urging forcefrom the spring 48, and the force receiving part 28 a is formed outsidethe bank portion 14 h in a top view. Thereby, the force receiving part28 a of the piston 28 can more reliably receive the urging force fromthe spring 48, the outflow of the flush water in the water storage part14 j can be further restrained, and the state where the packing 20 isimmersed in the flush water can be more easily maintained.

Further, according to the flush water tank apparatus 4 of the firstembodiment of the present invention, the force receiving part 28 a ofthe piston 28 in the discharge valve hydraulic drive portion 14 islocated below the top portion 14 k of the bank portion 14 h in the statewhere the piston 28 is at the first position H1. Thereby, when thepiston 28 receives the urging force from the spring 48, the forcereceiving part 28 a receiving the urging force as a force point islocated below the top portion 14 k of the bank portion 14 h thatfunctions as a fulcrum. Therefore, when the force receiving part 28 a ofthe piston 28 receives the urging force, the piston 28 is less likely totilt in a biased direction with respect to the top portion 14 k of thebank portion 14 h, and the operation of the piston 28 can be made morestable. Accordingly, the outflow of the flush water in the water storagepart 14 j can be stably restrained, and the state where the packing 20is immersed in the flush water can be stably maintained.

Further, according to the flush water tank apparatus 4 of the firstembodiment of the present invention, the piston 28 of the dischargevalve hydraulic drive portion 14 further includes the upper outercircumference part 28 b formed on the upper side of the packing 20, andthe water passageway gap 29 is formed between the upper outercircumference part 28 b and the inner wall of the cylinder 14 a, theflush water passing through the water passageway gap. Thereby, the upperside of the packing 20 can be more easily immersed in the flush water.

Further, according to the flush water tank apparatus 4 of the firstembodiment of the present invention, the water passageway gap 29 isformed between the upper outer circumference part 28 b and the innerwall of the cylinder 14 a to be gradually smaller from the upper side tothe lower side of the cylinder 14 a. Thereby, as the piston 28 movesfrom the upper side to the lower side of the cylinder 14 a, the waterpassageway gap 29 formed between the upper outer circumference part 28 band the inner wall of the cylinder 14 a becomes smaller, the flush wateron the upper side of the packing 20 can hardly exit from the waterpassageway gap 29, and the upper side of the packing 20 can be moreeasily immersed in the flush water.

Further, the first embodiment of the present invention relates to theflush toilet apparatus 1 including the flush toilet main body 2 and theflush water tank apparatus 4 that can reduce the possibility that theoperation of the discharge valve hydraulic drive portion 14malfunctions.

A flush toilet apparatus according to a second embodiment of the presentinvention will be described below with reference to FIGS. 14 to 20.

Since a flush toilet apparatus 101 according to the second embodimenthas substantially the same structure as the flush toilet apparatusaccording to the first embodiment described above, differences betweenthe second embodiment and the first embodiment of the present inventionwill be mainly described, and similar parts will be described using thesame reference numerals in the drawings or the specification, or willnot be described.

The flush toilet apparatus 101 according to the second embodiment of thepresent invention includes a flush water tank apparatus 104, which ismounted on the rear portion of the flush toilet main body 2, accordingto the second embodiment of the present invention. The flush water tankapparatus 104 according to the second embodiment of the presentinvention is configured to drain flush water stored therein to the flushtoilet main body 2 based on an instruction signal from the remotecontroller 6 or the human sensor 8 and to wash the bowl 2 a with theflush water.

The flush water tank apparatus 104 includes a discharge valve hydraulicdrive portion 114 that is a discharge valve pull-up part configured topull up the discharge valve 12. Further, the flush water tank apparatus104 includes therein a first control valve 16 that is a water supplycontroller configured to control water supply to the discharge valvehydraulic drive portion 114 from tap water and an electromagnetic valve18 attached to the first control valve 16. Further, the flush water tankapparatus 104 includes a float apparatus 26 that is a valve controllerand a timing control mechanism configured to hold the pulled-updischarge valve 12 at a predetermined position.

The flush water tank apparatus 104 further includes a clutch mechanism130 that connects the discharge valve 12 and discharge valve hydraulicdrive portion 114 to pull up the discharge valve 12 using a drivingforce of the discharge valve hydraulic drive portion 114 and isdisengaged at a predetermined timing so that the discharge valve 12descends. The clutch mechanism 130 is provided in front in a movingdirection of a second rod 133 extending laterally from the dischargevalve hydraulic drive portion 114 and is configured to couple andrelease an operating part 133 a of the second rod 133 to/from a passivepart 176 of the clutch mechanism 130 coupled to the discharge valve 12.The clutch mechanism 130 is formed separately from a casing 113 of thedischarge valve 12 and is disposed apart from the outside of the casing113.

The clutch mechanism 130 includes the operating part 133 a located at adistal end of the second rod 133, the passive part 176 provided on anextension line in the moving direction of the second rod 133 extendinglaterally from the discharge valve hydraulic drive portion 114, anelastic member 178 for the passive part connected to the passive part176, a first support body 180 that supports the passive part 176 and theelastic member 178 for the passive part, an elastic member 182 for thesupport body connected to the first support body 180, a second supportbody 184 that supports the elastic member 182 for the support body, anda regulation part 186 that regulates movement of the passive part 176 inthe moving direction of the second rod 133 and moves the passive part176 toward the side of the elastic member 178 for the passive part.

The operating part 133 a is formed to come into contact with a firstflat surface 176 a of the passive part 176. The first flat surface 176 aextends in a direction orthogonal to the moving direction of the secondrod 133. Therefore, the first flat surface 176 a is located in front ofthe operating part 133 a in a state where the elastic member 178 for thepassive part has a natural length. Accordingly, when the second rod 133moves toward the passive part 176, the operating part 133 a of thesecond rod 133 presses the first flat surface 176 a, and both the secondrod 133 and the passive part 176 move laterally. As the passive part 176and the first support body 180 move, the discharge valve 12 is pulled upby a couple member 188 as will be described below. An expansiondirection of the elastic member 182 for the support body is a lateraldirection, for example, the moving direction of the second rod 133. Thefirst support body 180 is connected to the elastic member 182 for thesupport body and moves in the expansion direction of the elastic member182 for the support body.

The passive part 176 forms an inclined surface 176 b on an opposite sideof the first flat surface 176 a. When the passive part 176 moves towardthe regulation part 186, the inclined surface 176 b comes into contactwith the regulation part 186, so that the inclined surface 176 b ispressed and moved toward the side of the elastic member 178 for thepassive part. Therefore, the contact between the second rod 133 and thepassive part 176 is released and the clutch mechanism 130 is releasedfrom the coupling. The passive part 176 is movable to disengage thecoupling of the clutch mechanism 130. At this time, the elastic member178 for the passive part is in a state of being contracted from itsnatural length. The expansion direction of the elastic member 178 forthe passive part is a vertical direction, for example, a directionorthogonal to the moving direction of the second rod 133. The elasticmember 178 for the passive part is formed of an elastic member such as aspring.

The first support body 180 and the passive part 176 move toward the sideof the discharge valve hydraulic drive portion 114 (toward the side ofthe discharge valve 12) to return to the original natural lengthposition by the elastic member 182 for the support body. Therefore, whenthe contact between the second rod 133 and the passive part 176 isreleased, the discharge valve 12 is in a free fall state. The elasticmember 182 for the support body is formed of an elastic member such as aspring.

The second support body 184 is fixed to the reservoir tank 10. Thesecond support body 184 is connected to the regulation part 186. Theregulation part 186 is formed to be in contact with the inclined surface176 b of the passive part 176. The regulation part 186 is disposed inthe moving direction of the passive part 176. The regulation part 186 isformed to move the passive part 176 so as to deviate from the second rod133 such that the contact between the first flat surface 176 a and thesecond rod 133 is released.

The first support body 180 and the upper end of the valve shaft framebody 12 a of the discharge valve 12 are connected to each other by acouple member 188. The couple member 188 is a wire or a bead chain, forexample. Therefore, when the first support body 180 is pressed by thesecond rod 133 and separated from the discharge valve 12, the dischargevalve 12 is physically pulled up by the couple member 188. The couplemember 188 has flexibility. The couple member 188 is disposed in acouple member conduit 189 curved between the first support body 180 andthe discharge valve 12. The couple member conduit 189 forms apipe-shaped passage that guides the couple member 188.

The casing 113 is formed above the discharge valve 12 to house thedischarge valve 12 therein and is formed in a cylindrical shape with anopening on a lower side. The casing 113 is formed separately from thedischarge valve hydraulic drive portion 114 and the clutch mechanism130, and is also disposed separately from the discharge valve hydraulicdrive portion 114. The casing 113 is fixed to the reservoir tank 10. Thecasing 113 is an independently disposed casing that is disposedindependently of the discharge valve hydraulic drive portion 114.

The discharge valve 12 is pulled up by a driving force of the dischargevalve hydraulic drive portion 114, the clutch mechanism 130 isdisengaged at a predetermined timing when the discharge valve 12 ispulled up to a predetermined height, and the discharge valve 12 descendsby its own weight. When the discharge valve 12 descends, the dischargevalve 12 is held by the float apparatus 26 for a predetermined time, anda time until the discharge valve 12 is seated on the water dischargeopening 10 a is adjusted.

The discharge valve hydraulic drive portion 114 will be described belowwith reference to FIGS. 14 to 20.

As shown in FIG. 14 and the like, the discharge valve hydraulic driveportion 114 is configured to drive the discharge valve 12 using a watersupply pressure of the flush water supplied from the tap water. Thedischarge valve hydraulic drive portion 114 includes a cylinder 114 a towhich the tap water supplied from the first control valve 16 is suppliedas flush water, a piston 128 slidably disposed in the cylinder 114 a, afirst rod 132 extending through a first through-hole portion 114 f,which is formed in the cylinder 114 a, from the piston 128, and a secondrod 133 extending through a second through-hole portion 114 q, which isformed in the cylinder 114 a, from the piston 128. The discharge valvehydraulic drive portion 114 is formed of resin.

A spring 48, which is an urging member, is disposed inside the cylinder114 a to urge the piston 128 toward the side of a first position H11.

The cylinder 114 a forms a horizontal cylinder that is oriented in ahorizontal direction. The cylinder 114 a accepts the piston 128 in aslidable manner in a lateral direction. An axis of the cylinder 114 aextends in the horizontal direction.

The first through-hole portion 114 f is formed on a side wall of thecylinder 114 a on a first position side. The first through-hole portion114 f includes a bank portion 114 h that rises toward the inside of thecylinder from a peripheral portion of a through hole formed in the sidewall of the cylinder 114 a, and a flow straightening portion 114 sformed such that a diameter of an inner wall at a top portion issubstantially constant in the moving direction of the first rod 132. Thebank portion 114 h is formed in an annular shape around the first rod132 in a top view. The flow straightening portion 114 s is formed fromthe top portion of the bank portion 114 h to a downstream side by apredetermined distance. The flow straightening portion 114 s forms ahorizontal wall extending in the horizontal direction. The flowstraightening portion 114 s extends substantially parallel to an outerwall of the first rod 132, and forms a flow channel having asubstantially constant width between the flow straightening portion 114s and the first rod 132. Thereby, it is possible to restrain turbulenceof the flow of the flush water passing between the flow straighteningportion 114 s and the first rod 132.

The discharge valve hydraulic drive portion 114 further includes aninlet 114 l that is formed in the cylinder 114 a and into which theflush water flows, a first discharge part 114 m provided separately fromthe inlet 114 l to cause the flush water to drain from the inside of thecylinder 114 a, and a second discharge part 114 n provided separatelyfrom the first discharge part 114 m and formed between the first rod 132and the first through-hole portion 114 f and between the piston 128 andthe first through-hole portion 114 f.

The inlet 114 l is connected to the drive part water supply passage 34a. The inlet 114 l is connected to a portion of the cylinder 114 a on anupstream side of the first position H11. The inlet 114 l forms a flowchannel communicating with an upstream side of the piston 128. The flushwater flowing out from the first control valve 16 flows into thecylinder 114 a from the inlet 114 l. The flush water flows into thecylinder 114 a using the water supply pressure of the tap water.Therefore, the piston 128 in the cylinder 114 a is pushed up against anurging force of the spring 48 by the flush water flowing into thecylinder 114 a. Only the tap water is supplied to the cylinder 114 a asflush water, and the flush water once supplied to the reservoir tank 10does not flow into the cylinder 114 a. Not only the piston 128 moves inthe lateral direction in the cylinder 114 a, but also the piston 128 maymove in another direction (for example, an oblique direction or anup-down direction) in the cylinder 114 a which may be disposed in theoblique direction or the up-down direction.

The first through-hole portion 114 f is connected to a drive part drainpassage 134 b, and the first discharge part 114 m extends into the drivepart drain passage 134 b. A distal end of the first discharge part 114 mforms an outflow hole to the drive part drain passage 134 b. The drivepart drain passage 134 b is a drain pipe. The first discharge part 114 mis formed to open and close a first discharge passageway inlet 170 a ofa first discharge passageway 170 through which the flush water isdrained from the inside of the cylinder 114 a to the outside of thecylinder 114 a by the first rod 132 and the first through-hole portion114 f. The first discharge part 114 m is configured such that when thepiston 128 is located at the first position H11, the first dischargepassageway inlet 170 a of the first discharge passageway 170 is closedby the first rod 132 and the first through-hole portion 114 f and thefirst discharge passageway 170 is closed. Further, the first dischargepart 114 m is configured such that when piston 128 reaches acommunication position (for example, a predetermined position on afurther back side from a disengagement position of the clutchmechanism)among from the first position H11 to a second position H12 andis located on a further back side after reaching, the first dischargepassageway inlet 170 a of the first discharge passageway 170 is openedby the first rod 132 and the first through-hole portion 114 f and thefirst discharge passageway 170 is in an open state. The first dischargepart 114 m has a switching function such as a switching valve between aclosed state and an open state of the first discharge passageway 170.The first discharge part 114 m has a function of forming a maindischarge passageway of the flush water from the cylinder 114 a. Inaddition, the first discharge part 114 m has a function of forming amain water supply passageway of the flush water to the reservoir tank10.

The first discharge passageway 170 of the first discharge part 114 m isformed by a passage extending to the inside of the first rod 132. Thefirst discharge passageway 170 is formed by a hollow internal passage ofthe first rod 132. The first discharge passageway inlet 170 a of thefirst discharge passageway 170 is opened on a side surface of the firstrod 132. When the piston 128 moves to be pushed forward up to the secondposition H12 located on the back side from the first position H11, thewater flowing into the cylinder 114 a flows out by passing from thefirst discharge part 114 m through the drive part drain passage 134 b.In other words, the drive part water supply passage 34 a and the drivepart drain passage 134 b communicate with each other via the inside ofthe cylinder 114 a when the piston 128 moves up to the second positionH12.

The second discharge part 114 n is formed between the first rod 132 andthe first through-hole portion 114 f and between the piston 128 and thefirst through-hole portion 114 f. The second discharge part 114 ncommunicates a pressure chamber on the inlet side of the discharge valvehydraulic drive portion 114 with a space inside the reservoir tank 10.The second discharge part 114 n forms a second discharge passageway 172from the cylinder 114 a. When the piston 128 is located at the firstposition H11, the second discharge part 114 n keeps the second dischargepassageway 172 open. The second discharge passageway 172 is always in anopen state regardless of the position of the piston 128. The seconddischarge passageway 172 is formed from, for example, a slight gapbetween an outer surface of the first rod 132 and the first through-holeportion 114 f, but a water passageway for the second dischargepassageway 172 may be provided in the first rod 132 as a modification.Some of the flush water flowing into the cylinder 114 a flows out fromthe second discharge part 114 n in the gap between the first rod 132 andthe first through-hole portion 114 f. The flush water flowing out fromthe second discharge part 114 n flows into the reservoir tank 10. Sincethe second discharge part 114 n is relatively narrow and has a largeflow channel resistance, even when the flush water flows out from thesecond discharge part 114 n, the pressure in the cylinder 114 a risesdue to the flush water flowing into the cylinder 114 a from the drivepart water supply passage 34 a, and the piston 128 is pushed up againstthe urging force of the spring 48.

A minimum cross-sectional area value of the second discharge passageway172 of the second discharge part 114 n is smaller than that of the firstdischarge passageway 170 of the first discharge part 114 m. The minimumcross-sectional area value of the second discharge passageway 172 of thesecond discharge part 114 n is equal to or less than half of the minimumcross-sectional area value of the first discharge passageway 170 of thefirst discharge part 114 m, and the second discharge part 114 n forms anauxiliary drain flow channel relative to the first discharge part 114 m.The second discharge part 114 n has a function of forming an auxiliarydischarge passageway of the flush water from the cylinder 114 a.

The second discharge passageway 172 of the second discharge part 114 nincludes a first flow channel 114 o extending along a lower surfaceportion 128 c between the top portion 114 k of the bank portion 114 hand a lower surface portion 128 c in the state where the piston 128 isat the first position H11, and a third flow channel 114 r extendinglaterally between the first rod 132 and the inner wall of the firstthrough-hole portion 114 f in the state where the piston 128 is at thefirst position H11. The first flow channel 114 o forms a flow channelwith a relatively small gap because the top portion 114 k and the lowersurface portion 128 c are substantially in contact with each other whenthe piston 128 is at the first position H11. The first flow channel 114o and the third flow channel 114 r form a flow channel that bends in anL shape in a cross-sectional view. Further, the piston 128 and thecylinder 114 a may be configured such that the top portion 114 k and thelower surface portion 128 c do not come in contact with each other andthe first flow channel 114 o of the flow channel with a relatively smallgap is formed in the state where the piston 128 is at the first positionH11.

The shape of the second discharge part 114 n changes with the movementof the piston 128. Therefore, the total cross-sectional area value andthe minimum cross-sectional area value of the flow channel in the seconddischarge part 114 n change with the movement of the piston 128. Thesecond discharge part 114 n is formed such that as the piston 128 movesfrom the first position H11 to the second position H12, the totalcross-sectional area value and the minimum cross-sectional area value ofthe second discharge passageway 172 in the second discharge part 114 nare increased and pressure loss of the second discharge part 114 n isreduced. For example, as the piston 128 moves from the first positionH11 to the second position H12, the cross-sectional area of the minimumflow channel in the second discharge part 114 n increases. For example,the cross-sectional area of the minimum flow channel is the minimumcross-sectional area value of the second discharge passageway 172between the top portion 114 k and the lower surface portion 128 c, andthe minimum cross-sectional area value of the flow channel of the seconddischarge passageway 172 increases as the piston 128 moves toward theside of the second position. As the piston 128 moves from the firstposition H11 to the second position H12, the minimum cross-sectionalarea value of the flow channel of the second discharge passageway 172also increases.

When an outer diameter of the portion of the distal end side of thefirst rod 132 is formed smaller than an outer diameter of the portion ofthe proximal end side (piston connection side), the second dischargepart 114 n is formed such that as the piston 128 and the first rod 132moves toward the side of the second position, the cross-sectional areaof the second discharge passageway 172 between the first rod 132 and theinner wall of the first through-hole portion 114 f, for example, thetotal cross-sectional area value and the minimum cross-sectional areavalue increase and the pressure loss of the second discharge part 114 nis reduced. At this time, the minimum cross-sectional area value (across-sectional area of the second discharge passageway 172 of thesecond discharge part 114 n corresponding to the discharge passageway ofthe second discharge part 14 n between the first rod 32 and the innerwall of the first through-hole portion 14 f as shown by the seconddischarge part 14 n in FIG. 7) of the second discharge passageway 172when the piston 128 is at the first position H11 is smaller than theminimum cross-sectional area value of the flow channel between the firstrod 132 and the inner wall of the first through-hole portion 114 f whenthe piston 128 is at the second position H12.

The cylinder 114 a is a substantially tubular member, and is formed in aconical shape in which the inner diameter of the inner wall 114 i of thecylinder 114 a gradually becomes smaller downward. The cylinder 114 a inthe second embodiment has substantially the same structure as thecylinder 14 a in the first embodiment except that the cylinder 114 a isdisposed sideways, and thus will not be described. For example, an innerdiameter R1 (see FIG. 5) of the cylinder 114 a at a portioncorresponding to the first position H11 of the piston 128 is the minimuminner diameter of the cylinder. The inner diameter of the cylinder 114 ais the same as that in the first embodiment, and thus will not bedescribed.

The first rod 132 is a rod-shaped member connected to the surface on theinlet side of the piston 128. The first rod 132 extends toward apressure chamber 114 g in the side of the inlet 114 l from the piston128 and extends outward through the first through-hole portion 114 f onthe side wall in the inlet side. The first rod 132 extends into thedrive part drain passage 134 b extending from the first through-holeportion 114 f. The proximal end of the first rod 132 is connected to thepiston 128, and the distal end of the first rod 132 is located insidethe drive part drain passage 134 b. The first rod 132 is a rod extendingtoward an opposite side of a second rod 133, which is an operating rodfor the clutch mechanism 130 extending from the piston 128 toward theclutch mechanism 130. The rod extending from the piston 128 through thethrough-hole portion formed in the cylinder 114 a is not necessarilylimited to distinguish the first rod 132 and the second rod 133 fromeach other, and the first rod 132 and the second rod 133 may be formedas a one rod.

The second rod 133 is a rod-shaped member connected to a surface of thepiston 128 on a back portion 114 t, and extends from the piston 128 tocouple the piston 128 and the discharge valve 12. The second rod 133extends from the piston 128 toward the side of the back portion 114 tand extends laterally to protrude from the inside of the cylinder 114 aby passing through the second through-hole portion 114 q formed in aside wall on the back side. The proximal end of the second rod 133 isconnected to the piston 128, and the distal end of the second rod 133acts on the passive part 176 of the clutch mechanism 130.

As shown in FIG. 16, a center axis G1 of the first rod 132 and a centeraxis G2 of the first through-hole portion 114 f are located on the sameaxis as a center axis G3 of the cylinder 114 a. A maximum outer diameterD1 out of outer diameters of the entire first rod 132 is smaller than aminimum inner diameter D2 out of inner diameters of the entire firstthrough-hole portion 114 f. In the present embodiment, the outerdiameter of the first rod 132 is formed to be substantially constantfrom the proximal end connected to the piston to the distal end. Theouter diameter of the distal end of the first rod 132 may be formedsmaller than the outer diameter of the proximal end of the first rod132.

In the present embodiment, the piston 128 is configured to movelaterally within the cylinder 114 a. The piston 128 moves from the firstposition H11 (see FIG. 14) to the second position H12 (see FIG. 19) whenthe flush water flows into the cylinder 114 a. The first position H11 ofthe piston 128 is located on the inlet 114 l, and the second positionH12 is located on the clutch mechanism 130 compared to the firstposition H11. The second position H12 is, for example, a position on theback side opposite to the inlet 114 l of the cylinder 114 a. The piston128 includes a force receiving part 28 a (see FIG. 16) that receives anurging force from the spring 48 and an upper outer circumference part 28b formed on the back side of the packing 20. The structure of the piston128 in the second embodiment is almost the same as the structure of thepiston 28 in the first embodiment, which will be referred to FIG. 6 andthe related description, and thus the detailed description of the piston128 will not be described.

Since the cylinder 114 a is formed in the conical shape, the waterpassageway gap 29 gradually becomes smaller as the piston 128 moves fromthe second position to the first position of the cylinder 114 a.

The packing 20 is attached to the piston 128 and has a function ofensuring watertightness of the seal between the inner wall surface ofthe cylinder 114 a and the piston 128. The packing 20 is a so-called Upacking having a U-shaped cross section. The packing 20 is an elasticmember formed of rubber.

As shown in FIG. 14, the flush water tank apparatus 104 further includesa speed reduction part 174 that reduces a flow rate of the flush waterdrained from the second discharge part 114 n. The speed reduction part174 is configured to reduce the flow rate of the flush water drainedfrom the second discharge part 114 n. The speed reduction part 174 is,for example, the drive part drain passage 134 b formed to cover theoutside of the first rod 132. The drive part drain passage 134 b extendsalong the outside of the first rod 132, and the flow rate of the flushwater flowing out from the second discharge part 114 n is reduced alongthe inner wall of the drive part drain passage 134 b. The speedreduction part 174 may be another means for reducing the flow rate ofthe flush water drained from the second discharge part 114 n. Forexample, a drain passage branch portion 134 c is provided on the drivepart drain passage 134 b, and the flow rate of the flush water may bereduced by branching at the drain passage branch portion 134 c.

The first control valve 16 will be described below.

The first control valve 16 is configured to control water supply to thedischarge valve hydraulic drive portion 114 and to control to supply andstop the water supply to the reservoir tank 10 based on an operation ofthe electromagnetic valve 18. In addition, the vacuum breaker 36 (seeFIG. 2) is provided in the drive part water supply passage 34 a locatedbetween the first control valve 16 and the discharge valve hydraulicdrive portion 114.

When the pilot valve 16 d is opened by the electromagnetic valve 18, themain valve body 16 a of the first control valve 16 is opened, and thetap water flowing in from the water supply pipe 38 is supplied to thedischarge valve hydraulic drive portion 114.

In addition, the tap water supplied from the first control valve 16 tothe discharge valve hydraulic drive portion 114 is supplied to thereservoir tank 10 or the overflow pipe 10 b through the drive part drainpassage 134 b by the first discharge part 114 m and/or the seconddischarge part 114 n. The first control valve 16 is provided with thepilot valve 16 e, and the pilot valve 16 e is opened and closed by thefloat switch 42.

The float switch 42 is connected to the pilot valve 16 e. The floatswitch 42 is configured to control the pilot valve 16 e based on thewater level in the reservoir tank 10 and to open and close a pilot valveport (not shown). In other words, the float switch 42 sends a signal tothe pilot valve 16 e to close the pilot valve port (not shown) when thewater level in the reservoir tank 10 reaches a predetermined waterlevel. In other words, the float switch 42 is configured to set thewater storage level in the reservoir tank 10 to a predetermined fullwater level WL which is a stopped water level. The float switch 42 isdisposed in the reservoir tank 10, and is configured to stop the watersupply to the discharge valve hydraulic drive portion 114 from the firstcontrol valve 16 when the water level of the reservoir tank 10 rises tothe full water level WL.

In addition, the drive part drain passage 134 b extending from thedischarge valve hydraulic drive portion 114 is provided with the drainpassage branch portion 134 c. One drive part drain passage 134 bbranched at the drain passage branch portion 134 c allows the water toflow out into the reservoir tank 10, and the other drive part drainpassage 134 b allows the water to flow out into the overflow pipe 10 b.Therefore, some of the flush water supplied from the discharge valvehydraulic drive portion 114 is drained to the flush toilet main body 2through the overflow pipe 10 b, and the remaining flush water is storedin the reservoir tank 10.

The controller 40 has a built-in CPU and a memory, and controlsconnected apparatus so as to execute a large washing mode and a smallwashing mode, which will be described below, based on a predeterminedcontrol program recorded in memory and the like. The controller 40 iselectrically connected to the remote controller 6, the human sensor 8,and the electromagnetic valve 18.

The float apparatus 26 will be described below. The float apparatus 26is configured such that the valve shaft frame body 12 a is lifted by apredetermined distance and the valve shaft frame body 12 a of thedischarge valve 12 descends after the valve shaft frame body 12 a, thecouple member 188, and the clutch mechanism 130 are detached from thedischarge valve hydraulic drive portion 114 to delay the closing of thewater discharge opening 10 a. Specifically, the float apparatus 26includes a float part 26 a and an engaging part 26 b interlocking withthe float part 26 a. On the other hand, a holding claw 12 g is formed ata proximal end of the valve shaft frame body 12 a of the discharge valve12 to engage with the engaging part 26 b.

A description will be given below with reference to FIGS. 14 to 20 withrespect to the flush water tank apparatus 104 according to the secondembodiment of the present invention and a series washing operations ofthe flush toilet apparatus 101 including the flush water tank apparatus104.

First, in the standby state of toilet washing shown in FIG. 14, thewater level in the reservoir tank 10 is at a predetermined full waterlevel WL, and in this state, the first control valve 16 is closed.Further, the float apparatus 26 is in a standby state. Next, when a userpushes a washing button of the remote controller 6, the remotecontroller 6 transmits an instruction signal for the toilet washing tothe controller 40. In the flush toilet apparatus 101 of the presentembodiment, even when a predetermined time elapses without the washingbutton of the remote controller 6 being pushed after the human sensor 8detects that the user leaves from the toilet, the instruction signal forthe toilet washing is transmitted to the controller 40.

The piston 128 of the discharge valve hydraulic drive portion 114 is atthe first position H11 in the cylinder 114 a. The first position H11 ofthe piston 128 is a position on the most inlet side in a movable range.The piston 128 is stopped in the cylinder 114 a. At this time, the lowerend 20 b of the packing 20 is located above the full water level WL ofthe reservoir tank 10. Therefore, the packing 20 is disposed in a regionto be directly supplied with the flush water from the tap water so as tobe immersed in the flush water stored in the reservoir tank 10 in whichwhat chemical for the toilet washing such as chlorine is charged by theuser is unknown. Therefore, it is possible to restrain the packing 20from being deteriorated by being immersed in such a chemical. Further,the packing 20 is immersed in the flush water directly supplied from thetap water, unlike the flush water stored in the reservoir tank 10 inwhich what washing agent for the toilet washing is charged by the useris unknown, thereby the deterioration of the packing 20 due to chlorinesuch as a toilet washing agent can also be restrained.

A deformation amount of the packing 20 in the state where the piston 128is at the first position H11 is a maximum deformation amount amongdeformation amounts of the elastic member at respective positions whilethe piston 128 moves from the first position H11 to the second positionH12. The deformation amount of the packing 20 is the same as that in thefirst embodiment, and thus will not be described.

In the standby state where the piston 128 is at the first position H11,the spring 48 is in the most extended state, and the lower surfaceportion 128 c of the piston 128 is in contact with the top portion 114 kof the bank portion 114 h. The piston 128 is urged toward the side ofthe first position by the spring 48, and is stopped in a state of beingin contact with the top portion 114 k.

When the piston 128 is located at the first position H11, the firstdischarge passageway inlet 170 a of the first discharge passageway 170of the first discharge part 114 m is closed by the first rod 132 and thefirst through-hole portion 114 f, and the first discharge passageway 170is closed. When the piston 128 is located at the first position H11, thesecond discharge part 114 n is formed between the first rod 132 and thefirst through-hole portion 114 f and between the piston 128 and thefirst through-hole portion 114 f. In other words, in the standby state,the second discharge passageway 172 formed between the first rod 132 andthe first through-hole portion 114 f is in an open state. Thus, as shownin FIG. 17, when the flush water flows into the cylinder 114 a, some ofthe flush water flows out from the second discharge passageway 172 ofthe second discharge part 114 n toward the side of the drive part drainpassage 134 b as indicated by an arrow F11.

In the standby state where the piston 128 is at the first position H11,the cross-sectional area of the flow channel in the second dischargepart 114 n is determined by the cross-sectional area of the flow channelbetween the first rod 132 and the first through-hole portion 114 f andthe cross-sectional area of the flow channel between the piston 128 andthe first through-hole portion 114 f. The cross-sectional area of theminimum flow channel in the second discharge part 114 n is thecross-sectional area of the first flow channel 114 o, and since the topportion 114 k and the lower surface portion 128 c are substantially incontact with each other, the pressure loss of the second discharge part114 n becomes larger.

Next, upon receiving the instruction signal for the toilet washing, thecontroller 40 allows the electromagnetic valve 18 (FIG. 14) provided inthe first control valve 16 to operate, and allows the pilot valve 16 don the electromagnetic valve side to be separated from the pilot valveport. Thus, the pressure in the pressure chamber 16 c drops, the mainvalve body 16 a is separated from the main valve port 16 b, and the mainvalve port 16 b is opened. When the first control valve 16 is opened,the flush water flowing in from the water supply pipe 38 is supplied tothe discharge valve hydraulic drive portion 114 via the first controlvalve 16. Thereby, the piston 128 of the discharge valve hydraulic driveportion 114 is pushed up, and the operating part 133 a of the second rod133 is advanced toward the passive part 176.

When the discharge valve 12 is pulled up, the holding claw 12 g providedon the valve shaft frame body 12 a of the discharge valve 12 pushes upand rotates the engaging part 26 b of the float apparatus 26, and theholding claw 12 g ascends beyond the engaging part 26 b.

After the standby state of the piston 128, for example, when the piston128 is advanced, the flush water flowing into the pressure chamber 114 bof the cylinder 114 a closer to the first position than the piston 128is retained mainly in the pressure chamber 114 b by the packing 20having a sealing function to generate a force that moves the piston 128toward the side of the second position.

As shown in FIG. 17, when the piston 128 and the second rod 133 movestoward the second position H12, the operating part 133 a comes intocontact with the first flat surface 176 a of the passive part 176, andthe passive part 176 and the first support body 180 are pushed laterallywhile contracting the elastic member 182 for the support body. Thereby,the couple member 188 connected to the first support body 180 is pulledup, and the discharge valve 12 is pulled up by the couple member 188.Therefore, when the discharge valve 12 is pulled up, the flush water inthe reservoir tank 10 is drained from the water discharge opening 10 ato the flush toilet main body 2.

Until the clutch mechanism 130 is disengaged while the piston 128 movesfrom the first position H11 to the second position H12, the seconddischarge passageway 172 formed between the first rod 132 and the firstthrough-hole portion 114 f is in an open state. Thereby, as indicated byan arrow F11, some of the flush water flowing into the cylinder 114 aflows out from the second discharge passageway 172 of the seconddischarge part 114 n toward the side of the drive part drain passage 134b. Since the outflow of the flush water from the second dischargepassageway 172 is relatively small, the piston 128 is pushed toward thesecond position H12 as planned. On the other hand, the first dischargepassageway inlet 170 a of the first discharge passageway 170 is closedby the first rod 132 and the first through-hole portion 114 f, and thefirst discharge passageway 170 of the first discharge part 114 m isclosed.

Next, as shown in FIG. 18, when the passive part 176 is further advancedand pressed toward the side of the regulation part 186, the inclinedsurface 176 b comes into contact with the regulation part 186, so thatthe inclined surface 176 b is pressed to the elastic member 178 for thepassive part, and the passive part 176 moves toward the side of theelastic member 178 for the passive part. Therefore, the contact betweenthe second rod 133 and the passive part 176 is released, and thecoupling of the clutch mechanism 130 is released. In other words, whenthe discharge valve 12 is pulled up to a predetermined height, thepassive part 176 of the clutch mechanism 130 hits the regulation part186, and the clutch mechanism 130 is disengaged. Even after the clutchmechanism 130 is disengaged, the first discharge passageway 170 of thefirst discharge part 114 m is in a closed state until the firstdischarge passageway inlet 170 a is opened, and as indicated by an arrowF12, some of the flush water flows out from the second dischargepassageway 172 of the second discharge part 114 n toward the side of thedrive part drain passage 134 b.

Next, when the clutch mechanism 130 is disengaged, the discharge valve12 starts to descend toward the water discharge opening 10 a due to itsown weight. The holding claw 12 g of the descending discharge valve 12engages with the engaging part 26 b of the float apparatus 26, and thedischarge valve 12 is held at a predetermined height by the engagingpart 26 b. When the discharge valve 12 is held by the engaging part 26b, the water discharge opening 10 a is maintained in an open state, andflush water in the reservoir tank 10 is maintained to be drained to theflush toilet main body 2. At this time, the pilot valve 16 d is still inthe open state, and the flush water flowing in from the water supplypipe 38 is supplied to the discharge valve hydraulic drive portion 114via the first control valve 16.

As shown in FIG. 19, the piston 128 and the first rod 132 are furtherpushed forward to reach the second position H12. In this process, whenthe piston 128 is advanced up to a communication position (a fourthposition H14 of the piston 128 in which a communication flow channel isformed) of the piston 128, a first discharge passageway inlet 170 a isopened from the first discharge passageway start position 132 a of thefirst rod 132 appearing in the cylinder 114 a so as to correspond to thecommunication position of the piston 128. The fourth position H14 islocated at a position closer to the back side of the piston than thedisengagement position where the clutch mechanism 130 is disengaged andat a position slightly closer to the inlet side (front side) than thesecond position H12. The distance from the connection portion of thefirst rod 132 with the piston 128 to the first discharge passagewaystart position 132 a, that is, the distance from the first position H11to the fourth position H14 is equal to or more than two-thirds of themovable distance of the piston 128 in the cylinder 114 a. When the firstdischarge passageway inlet 170 a of the first discharge passageway 170is opened by the first rod 132 and the first through-hole portion 114 f,the first discharge passageway 170 of the first discharge part 114 m isopened. Thereby, as indicated by an arrow F13, the flush water isdrained from the first discharge passageway 170 to the drive part drainpassage 134 b, and the flush water is discharged as main water supplyfrom the discharge part at the downstream end of the drive part drainpassage 134 b into the reservoir tank 10. At this time, as indicated byan arrow F14, some of the flush water also flows out from the seconddischarge passageway 172 of the second discharge part 114 n toward theside of the drive part drain passage 134 b.

In the second discharge part 114 n in the state where the piston 128 isat the second position H12, the top portion 114 k and the lower surfaceportion 128 c are separated from each other, the minimum cross-sectionalarea value of the flow channel of the first flow channel 114 oincreases. On the other hand, the minimum cross-sectional area value ofthe flow channel of the third flow channel 114 r remains constant. Inthis way, as the piston 128 moves toward the second position H12, thetop portion 114 k and the lower surface portion 128 c are separated fromeach other, the cross-sectional area of the flow channel of the firstflow channel 114 o increases, the total cross-sectional area value andthe minimum cross-sectional area value of the flow channel in the seconddischarge part 114 n increase, and the pressure loss of the seconddischarge part 114 n is reduced. In the state where the piston 128 isheading for the second position H12, the clutch mechanism 130 isdisengaged. When the clutch mechanism 130 is disengaged as describedabove, the minimum cross-sectional area value of the flow channel of thesecond discharge part 114 n is a maximum cross-sectional area value ofthe flow channel within the range of change from the first position H11to the second position H12 of the piston 128. Therefore, when the clutchmechanism 130 is disengaged, the pressure loss of the second dischargepart 114 n is a minimum pressure loss in the range of change incorresponding pressure loss from the first position H11 to the secondposition H12 of the piston 128.

Next, when the water level in the reservoir tank 10 drops, the floatswitch 42 for detecting the water level in the reservoir tank 10 isturned off. When the float switch 42 is turned off, the pilot valve 16 eis opened. Therefore, the flush water is supplied from the first controlvalve 16 into the reservoir tank 10 via the drive part water supplypassage 34 a and the drive part drain passage 134 b. The controller 40allows the electromagnetic valve 18 to be closed when a predeterminedtime has elapsed from the opening of the electromagnetic valve 18, andallows the pilot valve 16 d on the electromagnetic valve side to beclosed. On the other hand, since the pilot valve 16 e is opened, theopen state of the first control valve 16 is maintained and the watersupply to the reservoir tank 10 is continued.

In addition, when the water level in the reservoir tank 10 drops up tothe predetermined water level WL1, the float part 26 a of the floatapparatus 26 descends, which moves the engaging part 26 b. Thus, theengagement between the valve shaft frame body 12 a and the engaging part26 b is released, and the valve shaft frame body 12 a and the dischargevalve 12 start to descend again.

Thereby, the discharge valve 12 is seated on the water discharge opening10 a, and the water discharge opening 10 a is closed. Since the floatswitch 42 is still in the off state, the open state of the first controlvalve 16 is maintained, and the water supply to the reservoir tank 10 iscontinued. The flush water supplied through the drive part drain passage134 b reaches the drain passage branch portion 134 c, some of the flushwater branched at the drain passage branch portion 134 c flows into theoverflow pipe 10 b, and the remaining flush water is stored in thereservoir tank 10. The flush water flowing into the overflow pipe 10 bflows into the flush toilet main body 2, and is used to refill the bowl2 a. On the other hand, the water level in the reservoir tank 10 risesdue to the flush water flowing into the reservoir tank 10 in the statewhere the discharge valve 12 is closed.

As shown in FIG. 20, when the water level in the reservoir tank 10 risesto the predetermined full water level WL, the float switch 42 is turnedon. When the float switch 42 is turned on, the pilot valve 16 e on thefloat switch side is closed. Thereby, since the pilot valve 16 e isclosed, the first control valve 16 is closed and the water supply isstopped. After the first control valve 16 is closed and the water supplyto the discharge valve hydraulic drive portion 114 is stopped, the flushwater in the cylinder 114 a of the discharge valve hydraulic driveportion 114 gradually flows out from the first discharge part 114 m andthe second discharge part 114 n, and the piston 128 is pushed down bythe urging force of the spring 48 and returns to the first position H11.After the first discharge passageway inlet 170 a is closed along withthe return of the piston 128 to the first position H11, as indicated byan arrow F15, the flush water in the cylinder flows out from the seconddischarge passageway 172 toward the side of the drive part drain passage134 b. Therefore, as shown in FIG. 14, the apparatus in the reservoirtank 10 returns to the standby state.

According to the flush water tank apparatus 104 of the second embodimentof the present invention described above, the discharge valve hydraulicdrive portion 114 includes the inlet 114 l that is formed in thecylinder 114 a and into which the flush water flows, the first dischargepart 114 m provided separately from the inlet 114 l to cause the flushwater to drain from the inside of the cylinder 114 a, and the seconddischarge part 114 n provided separately from the first discharge part114 m and formed between the first rod 132 and the first through-holeportion 114 f. Thereby, when the water supply pressure of the flushwater to the cylinder 114 a suddenly fluctuates, for example, suddenlyrises in the state where the flow channel is not communicated or iscommunicated from the inlet 114 l to the first discharge part 114 m inthe cylinder 114 a, the second discharge part 114 n can soften theimpact of the sudden fluctuation in the pressure of the flush water, thepiston 128 can buffer the impact applied from the flush water, and theunstable operation of the piston 128 can be restrained.

According to the flush water tank apparatus 104 of the second embodimentof the present invention described above, the first discharge part 114 mis configured such that when the piston 128 is located at the firstposition H11, the first discharge passageway inlet 170 a is closed bythe first rod 132 and the first through-hole portion 114 f, and isfurther configured such that when the piston 128 reaches thecommunication position between the first position H11 and the secondposition H12, the first discharge passageway inlet 170 a is opened bythe first rod 132 and the first through-hole portion 114 f. With such arelatively simple configuration, when the piston 128 is located at thefirst position, the water supply pressure of the flush water does notescape toward the side of the first discharge passageway 170, and thewater supply pressure of the flush water is effectively used for themovement of the piston 128. When the piston 128 is located at thecommunication position between the first position H11 and the secondposition H12, the first discharge passageway 170 is opened, the flushwater is drained from the inside of the cylinder 114 a to the outside ofthe cylinder 114 a through the first discharge passageway 170, and thepiston 128 can easily return to the first position H11 from the secondposition H12 or the communication position.

According to the flush water tank apparatus 104 of the second embodimentof the present invention described above, since the first dischargepassageway 170 of the first discharge part 114 m is formed from thepassage extending inside of the first rod 132, when the first dischargepassageway is opened compared with the case where the passageway isformed on the outer surface portion of the first rod 132, the variationin the flow rate of the flush water flowing through the passage insidethe first rod 132 can be easily restrained. At the same time, when thepiston 128 is at the first position H11, the water supply pressure ofthe flush water does not escape toward the side of the first dischargepassageway 170, and the water supply pressure of the flush water iseffectively used for the movement of the piston 128. When the piston 128is located at the communication position, the first discharge passageway170 is opened, the flush water is drained from the inside of thecylinder 114 a to the outside of the cylinder 114 a through the firstdischarge passageway 170, and the piston 128 can easily return to thefirst position H11 from the second position H12 or a predeterminedposition.

According to the flush water tank apparatus 104 of the second embodimentof the present invention described above, the flush water tank apparatus104 further includes the speed reduction part 174 that reduces the flowrate of the flush water drained from the second discharge part 114 n.Thereby, the flow rate of the flush water drained from the seconddischarge part 114 n can be reduced. For example, even when the flushwater drained from the second discharge part 114 n is drained into thereservoir tank 10 from the position higher than the water level in thereservoir tank 10, scattering of the flush water can be restrained.

A flush toilet apparatus according to a third embodiment of the presentinvention will be described below with reference to FIGS. 21 to 28.

Since a flush toilet apparatus 201 according to the third embodiment hassubstantially the same structure as the flush toilet apparatus accordingto the second embodiment described above, differences between the thirdembodiment and the second embodiment of the present invention will bemainly described, and similar parts will be described using the samereference numerals in the drawings or the specification, or will not bedescribed.

As shown in FIG. 21, the flush toilet apparatus 201 according to thethird embodiment of the present invention includes a flush water tankapparatus 204, which is mounted on the rear portion of the flush toiletmain body 2, according to the third embodiment of the present invention.The flush water tank apparatus 204 according to the present embodimentis configured to drain flush water stored therein to the flush toiletmain body 2 based on an instruction signal from the remote controller 6or the human sensor 8 and to wash the bowl 2 a with the flush water.

The flush water tank apparatus 204 includes a discharge valve hydraulicdrive portion 214 that is a discharge valve pull-up part configured topull up the discharge valve 12. Further, the flush water tank apparatus204 includes therein a first control valve 16 that is a water supplycontroller configured to control water supply to the discharge valvehydraulic drive portion 214 from tap water.

The flush water tank apparatus 204 further includes a clutch mechanism130 that connects the discharge valve 12 and discharge valve hydraulicdrive portion 214 to pull up the discharge valve 12 using the dischargevalve hydraulic drive portion 214 and is disengaged at a predeterminedtiming so that the discharge valve 12 descends. The clutch mechanism 130of the third embodiment is the same as the clutch mechanism 130 of thesecond embodiment, and thus will not be described.

The discharge valve 12 is pulled up by a driving force of the dischargevalve hydraulic drive portion 214, the clutch mechanism 130 isdisengaged at a predetermined timing when the discharge valve 12 ispulled up to a predetermined height, and the discharge valve 12 descendsby its own weight. When the discharge valve 12 descends, the dischargevalve 12 is held by the float apparatus 26 for a predetermined time, anda time until the discharge valve 12 is seated on the water dischargeopening 10 a is adjusted.

The discharge valve hydraulic drive portion 214 will be described belowwith reference to FIGS. 21 to 28.

As shown in FIG. 21 and the like, the discharge valve hydraulic driveportion 214 is configured to drive the discharge valve 12 using a watersupply pressure of the flush water supplied from the tap water. Thestructure of the discharge valve hydraulic drive portion 214 of thethird embodiment is basically the same as the structure of the dischargevalve hydraulic drive portion 114 of the second embodiment except thefirst rod 132, and thus the same portions are denoted by the samereference numerals in the drawings and will not be described.

The discharge valve hydraulic drive portion 214 includes a first rod 232extending through a first through-hole portion 114 f, which is formed inthe cylinder 114 a, from the piston 128. The cylinder 114 a in the thirdembodiment has substantially the same structure as the cylinder 114 a inthe second embodiment, and thus will not be described.

The first rod 232 is a rod-shaped member connected to the surface on theinlet side of the piston 128. The first rod 232 extends toward apressure chamber 114 b on the inlet 114 l from the piston 128 andextends outward through the first through-hole portion 114 f on the sidewall on the inlet side. The first rod 232 extends into the drive partdrain passage 134 b extending from the first through-hole portion 114 f.The proximal end of the first rod 232 is connected to the piston 128,and the distal end of the first rod 232 is located inside the drive partdrain passage 134 b. The first rod 232 is a rod extending toward anopposite side of a second rod 133, which is an operating rod for theclutch mechanism 130 extending from the piston 128 toward the clutchmechanism 130. The rod extending from the piston 128 through thethrough-hole portion formed in the cylinder 114 a is not necessarilylimited to distinguish the first rod 232 and the second rod 133 fromeach other, and the first rod 232 and the second rod 133 may be formedas a one rod.

As shown in FIG. 22, the discharge valve hydraulic drive portion 214includes a first discharge part 214 m provided separately from the inlet114 l to cause the flush water to drain from the inside of the cylinder114 a, and a second discharge part 214 n provided separately from thefirst discharge part 214 m and formed between the first rod 232 and thefirst through-hole portion 114 f and between the piston 128 and thefirst through-hole portion 114 f.

The first discharge part 214 m extends into the drive part drain passage134 b. A distal end of the first discharge part 214 m forms an outflowhole to the drive part drain passage 134 b. The first discharge part 214m is formed to open and close a first discharge passageway inlet 270 aof a first discharge passageway 270 through which the flush water isdrained from the inside of the cylinder 114 a to the outside of thecylinder 114 a by the first rod 232 and the first through-hole portion114 f. As shown in FIGS. 21 and 24, the first discharge part 214 m isconfigured such that when the piston 128 is located at the firstposition H11, the first discharge passageway inlet 270 a of the firstdischarge passageway 270 is closed by the first rod 232 and the firstthrough-hole portion 114 f and the first discharge passageway 270 isclosed. As shown in FIG. 22, the first discharge part 114 m isconfigured such that when piston 128 reaches a communication position(for example, a predetermined position on a further back side from adisengagement position of the clutch mechanism) between the firstposition H11 to a second position H12 and is located on a further backside after reaching, the first discharge passageway inlet 270 a of thefirst discharge passageway 270 is opened by the first rod 232 and thefirst through-hole portion 114 f and the first discharge passageway 270is in an open state. The first discharge part 214 m has a switchingfunction such as a switching valve between a closed state and an openstate of the first discharge passageway 270. The first discharge part214 m has a function of forming a main discharge passageway of the flushwater from the cylinder 114 a. In addition, the first discharge part 214m has a function of forming a main water supply passageway of the flushwater to the reservoir tank 10.

As shown in FIG. 22, the first discharge passageway 270 of the firstdischarge part 214 m is formed such that a groove formed so as to cutout inward the side portion of the first rod 232 extends from a firstdischarge passageway start position 232 a to a distal end 232 b of thefirst rod 232 at the outer surface portion of the first rod 232. Thefirst discharge passageway start position 232 a is located at a positionaway from the proximal end on the piston side. The first dischargepassageway start position 232 a is the first discharge passageway startposition of the first rod 232 that appears in the cylinder 114 a so asto correspond to a communication position (a fourth position H14 wherethe communication flow channel is formed) of the piston 128. The firstdischarge passageway 270 forms a flow channel having a fan-shaped crosssection. The first discharge passageway 270 is formed on the outersurface portion of the first rod 232 and also forms a flow channelbetween the first rod 232 and the first through-hole portion 114 f. Thefirst discharge passageway inlet 270 a of the first discharge passageway270 is formed in such a manner that when the groove of the firstdischarge passageway 270 is located closer to the inside of the cylinderthan the first through-hole portion 114 f as the first rod 232 moves,the groove of the first discharge passageway 270 is opened laterallyinside the cylinder rather than the first through-hole portion 114 f. Asshown in FIG. 23, the first discharge passageways 270 are formed at fourlocations along the outer periphery of the first rod 232 in a front viewseen from the drive part drain passage 134 b in an axial direction ofthe first rod 232. A central angle of the fan shape in the cross sectionof the second discharge passageway 272 is about 72 degrees. The fourfirst discharge passageways 270 are similarly formed from the firstdischarge passageway start position 232 a to the distal end. Thedistance from the connection portion of the first rod 132 with thepiston 128 to the first discharge passageway start position 232 a, thatis, the distance from the first position H11 to the fourth position H14is more than two-thirds of the movable distance of the piston 128 in thecylinder 114 a.

The second discharge part 214 n is formed between the first rod 232 andthe first through-hole portion 114 f and between the piston 128 and thefirst through-hole portion 114 f. The second discharge part 214 ncommunicates a pressure chamber 114 b on the inlet side of the dischargevalve hydraulic drive portion 214 with a space inside the reservoir tank10. The second discharge part 214 n forms a second discharge passageway272 from the cylinder 114 a. The second discharge passageway 272 isformed from, for example, a slight gap between an outer surface of thefirst rod 232 and the first through-hole portion 114 f. The seconddischarge passageway 272 may further include, for example, a groove 272a in which the side portion of the first rod 232 is cut out inward froma proximal end 232 c to a distal end 232 b of the first rod 232. Thegroove 272 a of the second discharge passageway 272 forms a flow channelhaving a fan-shaped cross section. Therefore, when the piston 128 islocated at the first position H11, the second discharge passageway 272of the second discharge part 214 n is in an open state. The seconddischarge passageway 272 is always in an open state regardless of theposition of the piston 128. Some of the flush water flowing into thecylinder 114 a flows out from the second discharge part 214 n in the gapbetween the first rod 232 and the first through-hole portion 114 f. Theflush water flowing out from the second discharge part 214 n flows intothe reservoir tank 10. Since the second discharge part 214 n isrelatively narrow and has a large flow channel resistance, even when theflush water flows out from the second discharge part 214 n, the pressurein the cylinder 114 a rises due to the flush water flowing into thecylinder 114 a from the drive part water supply passage 34 a, and thepiston 128 is pushed up against the urging force of the spring 48.

A minimum cross-sectional area value of the second discharge passageway272 of the second discharge part 214 n is smaller than that of the firstdischarge passageway 270 of the first discharge part 214 m. The minimumcross-sectional area value of the second discharge passageway 272 of thesecond discharge part 214 n is equal to or less than half of the minimumcross-sectional area value of the first discharge passageway 270 of thefirst discharge part 214 m, and the second discharge part 214 n forms anauxiliary drain flow channel relative to the first discharge part 214 m.

As shown in FIG. 23, the second discharge passageway 272 is formed atone location along the outer periphery of the first rod 232 in a frontview seen from the drive part drain passage 134 b in an axial directionof the first rod 232. A central angle of the fan shape in the crosssection of the second discharge passageway 272 is about 72 degrees.

As shown in FIG. 22, a bank portion 114 h extends to the first positionH11 in a portion corresponding to the second discharge passageway 272,but is formed to have a shorter length in a portion corresponding to thefirst discharge passageway 270. Even with the bank portion 114 h andfirst rod 232, the second discharge passageway 272 of the seconddischarge part 214 n includes a first flow channel 114 o extendinglaterally with respect to a lower surface portion 128 c between the topportion 114 k of the bank portion 114 h and a lower surface portion 128c in the state where the piston 128 is at the first position H11, and athird flow channel 114 r extending laterally between the first rod 232and the inner wall of the first through-hole portion 114 f in the statewhere the piston 128 is at the first position H11. The third flowchannel 114 r forms a flow channel between an outer surface of theportion other than the groove 272 a of the first rod 232 and the innerwall of the first through-hole portion 114 f. The third flow channel 114r may include the groove 272 a or the flow channel between the groove272 a and the inner wall of the first through-hole portion 114 f.

The shape of the second discharge part 214 n changes with the movementof the piston 128. Therefore, the total cross-sectional area value andthe minimum cross-sectional area value of the flow channel in the seconddischarge part 214 n change with the movement of the piston 128. Thesecond discharge part 214 n is formed such that as the piston 128 movesfrom the first position H11 to the second position H12, the totalcross-sectional area value and the minimum cross-sectional area value ofthe second discharge passageway 272 in the second discharge part 214 nare increased and pressure loss of the second discharge part 214 n isreduced. For example, as the piston 128 moves from the first positionH11 to the second position H12, the cross-sectional area of the minimumflow channel in the second discharge part 214 n increases. For example,the cross-sectional area of the minimum flow channel is the minimumcross-sectional area value of the second discharge passageway 272between the top portion 114 k of the bank portion 114 h and the lowersurface portion 128 c of the piston 128. As the piston 128 moves fromthe first position H11 to the second position H12, the minimumcross-sectional area value of the flow channel of the second dischargepassageway 272 also increases.

When an outer diameter of the portion of the distal end side of thefirst rod 232 is formed smaller than an outer diameter of the portion ofthe proximal end side, the second discharge part 214 n is formed suchthat as the piston 128 and the first rod 232 move toward the side of thesecond position, the cross-sectional area of the second dischargepassageway 272 between the first rod 232 and the inner wall of the firstthrough-hole portion 114 f, for example, the total cross-sectional areavalue and the minimum cross-sectional area value increase and thepressure loss of the second discharge part 214 n is reduced. At thistime, the minimum cross-sectional area value (a cross-sectional area ofthe second discharge passageway 272 of the second discharge part 214 ncorresponding to the discharge passageway of the second discharge part14 n between the first rod 32 and the inner wall of the firstthrough-hole portion 14 f as shown by the second discharge part 14 n inFIG. 7) of the second discharge passageway 272 when the piston 128 is atthe first position H11 is smaller than the minimum cross-sectional areavalue of the flow channel between the first rod 232 and the inner wallof the first through-hole portion 114 f when the piston 128 is at thesecond position H12.

A description will be given below with reference to FIGS. 21 to 28 withrespect to the flush water tank apparatus 204 according to the thirdembodiment of the present invention and a series washing operations ofthe flush toilet apparatus 201 including the flush water tank apparatus204. Since the washing operation of the flush water tank apparatus 204in the third embodiment is substantially the same as the washingoperation of the flush water tank apparatus 104 in the secondembodiment, the first discharge part 214 m and the second discharge part214 n will be mainly described, and the repeated portions will bereferred to the description of the second embodiment and will not bedescribed.

As shown in FIGS. 21 and 24, when the piston 128 is located at the firstposition H11, the first discharge passageway inlet 270 a of the firstdischarge passageway 270 of the first discharge part 214 m is closed bythe first rod 232 and the first through-hole portion 114 f, and thefirst discharge passageway 270 is closed. When the piston 128 is locatedat the first position H11, the first discharge passageway inlet 270 a ofthe first discharge passageway 270 of the first rod 232 is locatedcloser to the drive part drain passage 134 b than the top portion 114 kof the bank portion 114 h. When the piston 128 is located at the firstposition H11, the second discharge part 214 n is formed between thefirst rod 232 and the first through-hole portion 114 f and between thepiston 128 and the first through-hole portion 114 f. In other words, inthe standby state, the second discharge passageway 272 formed betweenthe first rod 232 and the first through-hole portion 114 f is in an openstate. Thus, as shown in FIG. 25, when the flush water flows into thecylinder 114 a, some of the flush water flows out from the seconddischarge passageway 272 of the second discharge part 214 n toward theside of the drive part drain passage 134 b as indicated by an arrow F21.

Next, when the instruction signal for the toilet washing is received andthe first control valve 16 is open, the flush water flowing from thewater supply pipe 38 is supplied to the discharge valve hydraulic driveportion 214 through the first control valve 16. Thereby, the piston 128of the discharge valve hydraulic drive portion 214 is pushed up, and theoperating part 133 a of the second rod 133 is advanced toward thepassive part 176.

As shown in FIG. 25, when the piston 128 and the second rod 133 movestoward the second position H12, the operating part 133 a comes intocontact with the first flat surface 176 a of the passive part 176, andthe passive part 176 and the first support body 180 are pushed whilecontracting the elastic member 182 for the support body. Thereby, thecouple member 188 connected to the first support body 180 is pulled up,and the discharge valve 12 is pulled up by the couple member 188.Therefore, when the discharge valve 12 is pulled up, the flush water inthe reservoir tank 10 is drained from the water discharge opening 10 ato the flush toilet main body 2.

Until the clutch mechanism 130 is disengaged while the piston 128 movesfrom the first position H11 to the second position H12, the seconddischarge passageway 272 formed between the first rod 232 and the firstthrough-hole portion 114 f is an open state. Thereby, as indicated by anarrow F21, some of the flush water flowing into the cylinder 114 a flowsout from the second discharge passageway 272 of the second dischargepart 214 n toward the side of the drive part drain passage 134 b. Sincethe outflow of the flush water from the second discharge passageway 272is relatively small, the piston 128 is pushed toward the second positionH12 as planned. On the other hand, the first discharge passageway inlet270 a of the first discharge passageway 270 is closed by the first rod232 and the first through-hole portion 114 f, and the first dischargepassageway 270 of the first discharge part 214 m is closed.

Next, as shown in FIG. 26, when the passive part 176 is further advancedand pressed toward the regulation part 186, the contact between thesecond rod 133 and the passive part 176 is released, and the coupling ofthe clutch mechanism 130 is released. In other words, when the dischargevalve 12 reaches a predetermined height, the passive part 176 of theclutch mechanism 130 hits the regulation part 186, and the clutchmechanism 130 is disengaged. Even after the clutch mechanism 130 isdisengaged, the first discharge passageway 270 of the first dischargepart 214 m is in a closed state until the first discharge passagewayinlet 270 a is opened, and as indicated by an arrow F22, some of theflush water flows out from the second discharge passageway 272 of thesecond discharge part 214 n toward the side of the drive part drainpassage 134 b.

As shown in FIG. 27, the piston 128 and the first rod 232 are furtherpushed forward to reach the second position H12. In this process, whenthe piston 128 is advanced up to a communication position (a fourthposition H14 of the piston 128 in which a communication flow channel isformed) of the piston 128, a first discharge passageway inlet 270 a isopened from the first discharge passageway start position 232 a of thefirst rod 232 appearing in the cylinder 114 a so as to correspond to thecommunication position of the piston 128. The fourth position H14 islocated at a position closer to the back side of the piston than thedisengagement position where the clutch mechanism 130 is disengaged andat a position slightly closer to the inlet side (front side) than thesecond position H12. When the first discharge passageway inlet 270 a ofthe first discharge passageway 270 is opened by the first rod 232 andthe first through-hole portion 114 f, the first discharge passageway 270of the first discharge part 214 m is opened. Thereby, as indicated by anarrow F23, the flush water is drained from the first dischargepassageway 270 to the drive part drain passage 134 b, and the flushwater is discharged as main water supply from the discharge part at thedownstream end of the drive part drain passage 134 b into the reservoirtank 10. At this time, as indicated by an arrow F24, some of the flushwater also flows out from the second discharge passageway 272 of thesecond discharge part 214 n toward the side of the drive part drainpassage 134 b.

On the other hand, since the pilot valve 16 e is opened, the open stateof the first control valve 16 is maintained and the water supply to thereservoir tank 10 is continued. In addition, when the water level in thereservoir tank 10 drops up to the predetermined water level WL1, thefloat part 26 a of the float apparatus 26 descends, which moves theengaging part 26 b. Thus, the engagement between the valve shaft framebody 12 a and the engaging part 26 b is released, and the valve shaftframe body 12 a and the discharge valve 12 start to descend again.

Thereby, the discharge valve 12 is seated on the water discharge opening10 a, and the water discharge opening 10 a is closed. Since the floatswitch 42 is still in the off state, the open state of the first controlvalve 16 is maintained, and the water supply to the reservoir tank 10 iscontinued. The flush water supplied through the drive part drain passage134 b reaches the drain passage branch portion 134 c, some of the flushwater branched at the drain passage branch portion 134 c flows into theoverflow pipe 10 b, and the remaining flush water is stored in thereservoir tank 10. The flush water flowing into the overflow pipe 10 bflows into the flush toilet main body 2, and is used to refill the bowl2 a. On the other hand, the water level in the reservoir tank 10 risesdue to the flush water flowing into the reservoir tank 10 in the statewhere the discharge valve 12 is closed.

As shown in FIG. 28, after the first control valve 16 is closed and thewater supply to the discharge valve hydraulic drive portion 214 isstopped, the flush water in the cylinder 114 a of the discharge valvehydraulic drive portion 214 gradually flows out from the first dischargepart 214 m and the second discharge part 214 n, and the piston 128 ispushed down by the urging force of the spring 48 and returns to thefirst position H11. After the first discharge passageway inlet 270 a isclosed along with the return of the piston 128 to the first positionH11, as indicated by an arrow F25, the flush water in the cylinder flowsout from the second discharge passageway 272 toward the side of thedrive part drain passage 134 b. Therefore, as shown in FIG. 21, theapparatus in the reservoir tank 10 returns to the standby state.

According to the flush water tank apparatus 204 of the third embodimentof the present invention described above, the discharge valve hydraulicdrive portion 114 includes the inlet 114 l that is formed in thecylinder 114 a and into which the flush water flows, the first dischargepart 214 m provided separately from the inlet 114 l to cause the flushwater to drain from the inside of the cylinder 114 a, and the seconddischarge part 214 n provided separately from the first discharge part214 m and formed between the first rod 232 and the first through-holeportion 114 f. Thereby, when the water supply pressure of the flushwater to the cylinder 114 a suddenly fluctuates, for example, suddenlyrises in the state where the flow channel is not communicated or iscommunicated from the inlet 114 l to the first discharge part 214 m inthe cylinder 114 a, the second discharge part 214 n can soften theimpact of the sudden fluctuation in the pressure of the flush water, thepiston 128 can buffer the impact applied from the flush water, and theunstable operation of the piston 128 can be restrained.

According to the flush water tank apparatus 204 of the third embodimentof the present invention described above, the first discharge passageway270 of the first discharge part 214 m can be relatively easily formedfrom the groove formed on the outer surface portion of the first rod232. Therefore, when the piston 128 is located at the first positionH11, the water supply pressure of the flush water does not escape towardthe side of the first discharge passageway 270, and the water supplypressure of the flush water is effectively used for the movement of thepiston 128. When the piston 128 is located at the communicationposition, the first discharge passageway 270 is opened, the flush wateris drained from the inside of the cylinder 114 a to the outside of thecylinder 114 a through the first discharge passageway 270, and thepiston 128 can easily return to the first position H11 from the secondposition H12 or the predetermined position.

In the discharge valve hydraulic drive portion 214 according to thesecond embodiment of the present invention described above, as anexample, the second discharge passageway 172 is formed from the slightgap between the outer surface of the first rod 132 and the firstthrough-hole portion 114 f. However, as a modification without beinglimited to such a form, as shown in FIG. 29, the second dischargepassageway 172 of the second discharge part 114 n may further include aninternal passage 172 c extending into the first rod 132 from the seconddischarge passageway inlet 172 b that opens on the side surface of thefirst rod 132. By the second discharge passageway 172 including theinternal passage 172 c, the amount to be drained can be more stabilized.Such an internal passage 172 c may be connected to the first dischargepassageway 170 in the second embodiment. The minimum cross-sectionalarea value of the flow channel at the second discharge passageway inlet172 b and the internal passage 172 c is made smaller than the minimumcross-sectional area value of the flow channel at the internal passageof the first discharge passageway inlet 170 a and the first dischargepassageway 170.

What is claimed is:
 1. A flush water tank apparatus configured to supplyflush water to a flush toilet, the flush water tank apparatuscomprising: a reservoir tank configured to store flush water to besupplied to the flush toilet and includes a water discharge openingformed thereon, the water discharge opening being for draining storedthe flush water to the flush toilet; a discharge valve configured toopen and close the water discharge opening to supply the flush water tothe flush toilet and to stop a supply of the flush water to the flushtoilet; and a discharge valve hydraulic drive portion configured todrive the discharge valve using a water supply pressure of tap waterbeing supplied, the discharge valve hydraulic drive portion including: acylinder to which the tap water is supplied as the flush water; a pistonthat is slidably disposed in the cylinder and moves from a firstposition to a second position by the flush water flowing into thecylinder; a rod that extends from the piston through a through-holeportion formed in the cylinder; an elastic member that is provided onthe piston and has a sealing function between the piston and an innerwall of the cylinder; an inlet that is formed in the cylinder and intowhich the flush water flows; a first discharge part that is providedseparately from the inlet to discharge the flush water from an inside ofthe cylinder; and a second discharge part that is provided separatelyfrom the first discharge part and is formed between the rod and thethrough-hole portion and between the piston and the through-holeportion.
 2. The flush water tank apparatus according to claim 1, whereinthe first discharge part is formed in the cylinder.
 3. The flush watertank apparatus according to claim 1, wherein the first discharge part isformed such that an inlet of a first discharge passageway, through whichthe flush water is discharged from the inside of the cylinder to anoutside of the cylinder, is opened and closed by the rod and thethrough-hole portion, and the first discharge part is configured suchthat when the piston is located at the first position, the inlet of thefirst discharge passageway is closed by the rod and the through-holeportion and the first discharge passageway is closed, and is furtherconfigured such that when the piston reaches a communication positionamong from the first position to the second position, the inlet of thefirst discharge passageway is opened by the rod and the through-holeportion and the first discharge passageway is opened.
 4. The flush watertank apparatus according to claim 3, wherein the first dischargepassageway of the first discharge part is formed by a passage extendingin an inside of the rod from a first discharge passageway start positionof the rod appearing in the cylinder so as to correspond to thecommunication position of the piston, to a distal end of the rod.
 5. Theflush water tank apparatus according to claim 3, wherein the firstdischarge passageway of the first discharge part is formed by a grooveformed on an outer surface portion of the rod from a first dischargepassageway start position of the rod appearing in the cylinder so as tocorrespond to the communication position of the piston, to a distal endof the rod.
 6. The flush water tank apparatus according to claim 1,wherein a deformation amount of the elastic member in a state where thepiston is at the first position is a maximum deformation amount amongdeformation amounts of the elastic member at respective positions whilethe piston moves from the first position to the second position.
 7. Theflush water tank apparatus according to claim 6, wherein an innerdiameter of the cylinder at a portion corresponding to the firstposition of the piston is a minimum inner diameter among inner diametersof the cylinder.
 8. The flush water tank apparatus according to claim 6,wherein the discharge valve hydraulic drive portion further includes anurging member that is provided in the cylinder to urge the piston towarda side of the first position.
 9. The flush water tank apparatusaccording to claim 1, wherein the second discharge part is formed suchthat as the piston moves from the first position to the second position,a cross-sectional area of a flow channel in the second discharge part isincreased and a pressure loss of the second discharge part is reduced.10. The flush water tank apparatus according to claim 9, wherein thesecond discharge part is formed such that as the piston moves from thefirst position to the second position, a cross-sectional area of a flowchannel of the second discharge part between the rod and an inner wallof the through-hole portion is increased and the pressure loss of thesecond discharge part is reduced.
 11. The flush water tank apparatusaccording to claim 9, wherein the through-hole portion of the cylinderincludes a bank portion that rises from a peripheral portion of athrough hole at a bottom portion of the cylinder toward the inside ofthe cylinder, and the second discharge part includes a first flowchannel extending between a top portion of the bank portion and thepiston in a state where the piston is at the first position.
 12. Theflush water tank apparatus according to claim 9, further comprising: aclutch mechanism that couples the discharge valve and the dischargevalve hydraulic drive portion to pull up the discharge valve by thedischarge valve hydraulic drive portion and is disengaged at apredetermined timing to allow the discharge valve to descend, whereinthe cross-sectional area of the flow channel of the second dischargepart when the clutch mechanism is disengaged is a maximumcross-sectional area of the flow channel among cross-sectional areas ofthe flow channel of the second discharge part at respective positionswhile the piston moves from the first position to the second position.13. The flush water tank apparatus according to claim 1, wherein acenter axis of the rod and a center axis of the through-hole portion arelocated on the same axis as a center axis of the cylinder.
 14. The flushwater tank apparatus according to claim 1, wherein the through-holeportion further includes a flow straightening portion that is formedsuch that a diameter of an inner wall at a top portion thereof isconstant in a moving direction of the rod.
 15. The flush water tankapparatus according to claim 1, wherein a maximum outer diameter of therod is smaller than a minimum inner diameter of the through-holeportion.
 16. The flush water tank apparatus according to claim 1,wherein the flush water tank apparatus further includes a speedreduction part that reduces a flow rate of the flush water dischargedfrom the second discharge part.
 17. The flush water tank apparatusaccording to claim 1, wherein when the piston is at the first position,a lower end of the elastic member is located above a stopped water levelof the reservoir tank.
 18. The flush water tank apparatus according toclaim 17, wherein the cylinder of the discharge valve hydraulic driveportion is configured such that the elastic member is immersed in flushwater remaining in the cylinder in the state where the piston is locatedat the first position.
 19. The flush water tank apparatus according toclaim 18, wherein the piston of the discharge valve hydraulic driveportion is configured to move up and down in the cylinder, the firstposition is located to be lower than the second position, the cylinderincludes a bank portion that rises upward from a peripheral portion of athrough hole at a bottom portion thereof and a water storage partcapable of storing flush water remaining between the bank portion andthe inner wall of the cylinder, and an upper end of the elastic memberis located at a position lower than the top portion of the bank portionsuch that the elastic member is located in the water storage part in thestate where the piston is located at the first position.
 20. The flushwater tank apparatus according to claim 19, wherein the top portion ofthe bank portion is in contact with a lower surface portion of thepiston in the state where the piston is located at the first position.21. The flush water tank apparatus according to claim 20, wherein therod extends downward from the piston, and the bank portion of thecylinder is formed in an annular shape around the rod in a top view. 22.The flush water tank apparatus according to claim 20, wherein thedischarge valve hydraulic drive portion further includes an urgingmember that is provided in the cylinder and urges the piston toward aside of the first position, the piston includes a force receiving partthat receives an urging force from the urging member, and the forcereceiving part is formed outside the bank portion in a top view.
 23. Theflush water tank apparatus according to claim 22, wherein the forcereceiving part of the piston in the discharge valve hydraulic driveportion is located below the top portion of the bank portion in thestate where the piston is at the first position.
 24. The flush watertank apparatus according to claim 19, wherein the piston of thedischarge valve hydraulic drive portion further includes an upper outercircumference part that is formed on an upper side of the elasticmember, and a water passageway gap is formed between the upper outercircumference part and the inner wall of the cylinder, the flush waterpassing through the water passageway gap.
 25. The flush water tankapparatus according to claim 24, wherein the water passageway gap isformed between the upper outer circumference part and the inner wall ofthe cylinder to be gradually smaller from an upper side to a lower sideof the cylinder.
 26. A flush toilet apparatus comprising: the flushwater tank apparatus according to claim 1; and a flush toilet that iswashed with the flush water to be supplied from the flush water tankapparatus.